diff --git a/.gitignore b/.gitignore
index b61afb451912..58f783104044 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,6 +22,8 @@
 build/
 build-*/
 Testing/
+# Include iree.build package
+!compiler/bindings/python/iree/compiler/build/
 
 # Bazel artifacts
 **/bazel-*
diff --git a/compiler/bindings/python/CMakeLists.txt b/compiler/bindings/python/CMakeLists.txt
index 0a0b36474885..bc8119f07b61 100644
--- a/compiler/bindings/python/CMakeLists.txt
+++ b/compiler/bindings/python/CMakeLists.txt
@@ -234,6 +234,37 @@ add_mlir_python_modules(IREECompilerPythonModules
   )
 
 
+################################################################################
+# iree.build package
+# This is a pure Python part of the namespace, not rooted under iree.compiler
+# like the above. It is only using the same build support for compatibility
+# with the existing development flow.
+# If the build system for Python code is ever redone, this can just be
+# source namespace in the project definition.
+################################################################################
+
+# The iree.build package.
+declare_mlir_python_sources(IREECompilerBuildPythonPackage
+ROOT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/iree/build"
+SOURCES
+  __init__.py
+  __main__.py
+  executor.py
+  lang.py
+  main.py
+  net_actions.py
+  onnx_actions.py
+)
+
+add_mlir_python_modules(IREECompilerBuildPythonModules
+  ROOT_PREFIX "${_PYTHON_BUILD_PREFIX}/iree/build"
+  INSTALL_PREFIX "${_PYTHON_INSTALL_PREFIX}/iree/build"
+  DECLARED_SOURCES
+    IREECompilerBuildPythonPackage
+)
+
+add_dependencies(IREECompilerPythonModules IREECompilerBuildPythonModules)
+
 ################################################################################
 # Tools linked against the shared CAPI library
 ################################################################################
diff --git a/compiler/bindings/python/iree/build/__init__.py b/compiler/bindings/python/iree/build/__init__.py
new file mode 100644
index 000000000000..95ee3f74b26b
--- /dev/null
+++ b/compiler/bindings/python/iree/build/__init__.py
@@ -0,0 +1,12 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+import argparse
+
+from iree.build.lang import *
+from iree.build.main import *
+from iree.build.net_actions import *
+from iree.build.onnx_actions import *
diff --git a/compiler/bindings/python/iree/build/__main__.py b/compiler/bindings/python/iree/build/__main__.py
new file mode 100644
index 000000000000..bbaa9e1efb89
--- /dev/null
+++ b/compiler/bindings/python/iree/build/__main__.py
@@ -0,0 +1,11 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from .main import CliMain
+
+
+if __name__ == "__main__":
+    CliMain().run()
diff --git a/compiler/bindings/python/iree/build/executor.py b/compiler/bindings/python/iree/build/executor.py
new file mode 100644
index 000000000000..dcd02058b10e
--- /dev/null
+++ b/compiler/bindings/python/iree/build/executor.py
@@ -0,0 +1,516 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from typing import Callable, Collection, Generator, IO
+
+import abc
+import argparse
+import concurrent.futures
+import enum
+import inspect
+import multiprocessing
+import sys
+import time
+import traceback
+from pathlib import Path
+import threading
+
+_locals = threading.local()
+
+
+class FileNamespace(enum.StrEnum):
+    # Transient generated files go into the GEN namespace. These are typically
+    # not packaged for distribution.
+    GEN = enum.auto()
+
+    # Distributable parameter files.
+    PARAMS = enum.auto()
+
+    # Distributable, platform-neutral binaries.
+    BIN = enum.auto()
+
+    # Distributable, platform specific binaries.
+    PLATFORM_BIN = enum.auto()
+
+
+FileNamespaceToPath = {
+    FileNamespace.GEN: lambda executor: executor.output_dir / "genfiles",
+    FileNamespace.PARAMS: lambda executor: executor.output_dir / "params",
+    FileNamespace.BIN: lambda executor: executor.output_dir / "bin",
+    # TODO: This isn't right. Need to resolve platform dynamically.
+    FileNamespace.PLATFORM_BIN: lambda executor: executor.output_dir / "platform",
+}
+
+
+def join_namespace(prefix: str, suffix: str) -> str:
+    """Joins two namespace components, taking care of the root namespace (empty)."""
+    if not prefix:
+        return suffix
+    return f"{prefix}/{suffix}"
+
+
+class ClArg:
+    def __init__(self, name, dest: str, **add_argument_kw):
+        self.name = name
+        self.dest = dest
+        self.add_argument_kw = add_argument_kw
+
+    def define_arg(self, parser: argparse.ArgumentParser):
+        parser.add_argument(f"--{self.name}", dest=self.dest, **self.add_argument_kw)
+
+    def resolve(self, arg_namespace: argparse.Namespace):
+        try:
+            return getattr(arg_namespace, self.dest)
+        except AttributeError as e:
+            raise RuntimeError(
+                f"Unable to resolve command line argument '{self.dest}' in namespace"
+            ) from e
+
+
+class Entrypoint:
+    def __init__(
+        self,
+        name: str,
+        wrapped: Callable,
+        description: str | None = None,
+    ):
+        self.name = name
+        self.description = description
+        self._wrapped = wrapped
+
+    def cl_args(self) -> Generator[ClArg, None, None]:
+        sig = inspect.signature(self._wrapped)
+        for p in sig.parameters.values():
+            def_value = p.default
+            if isinstance(def_value, ClArg):
+                yield def_value
+
+    def __call__(self, *args, **kwargs):
+        parent_context = BuildContext.current()
+        bep = BuildEntrypoint(
+            join_namespace(parent_context.path, self.name),
+            parent_context.executor,
+            self,
+        )
+        parent_context.executor.entrypoints.append(bep)
+        with bep:
+            sig = inspect.signature(self._wrapped)
+            bound = sig.bind(*args, **kwargs)
+            bound.apply_defaults()
+
+            def filter(arg):
+                if isinstance(arg, ClArg):
+                    return arg.resolve(parent_context.executor.args_namespace)
+                return arg
+
+            new_args = [filter(arg) for arg in bound.args]
+            new_kwargs = {k: filter(v) for k, v in bound.kwargs.items()}
+            results = self._wrapped(*new_args, **new_kwargs)
+            if results is not None:
+                files = bep.files(results)
+                bep.deps.update(files)
+                bep.outputs.extend(files)
+                return files
+
+
+class Executor:
+    """Executor that all build contexts share."""
+
+    def __init__(
+        self, output_dir: Path, args_namespace: argparse.Namespace, stderr: IO
+    ):
+        self.output_dir = output_dir
+        self.verbose_level = 0
+        # Keyed by path
+        self.all: dict[str, "BuildContext" | "BuildFile"] = {}
+        self.entrypoints: list["BuildEntrypoint"] = []
+        self.args_namespace = args_namespace
+        self.stderr = stderr
+        BuildContext("", self)
+
+    def check_path_not_exists(self, path: str, for_entity):
+        existing = self.all.get(path)
+        if existing is not None:
+            formatted_stack = "".join(traceback.format_list(existing.def_stack))
+            raise RuntimeError(
+                f"Cannot add {for_entity} because an entity with that name was "
+                f"already defined at:\n{formatted_stack}"
+            )
+
+    def get_context(self, path: str) -> "BuildContext":
+        existing = self.all.get(path)
+        if existing is None:
+            raise RuntimeError(f"Context at path {path} not found")
+        if not isinstance(existing, BuildContext):
+            raise RuntimeError(
+                f"Entity at path {path} is not a context. It is: {existing}"
+            )
+        return existing
+
+    def get_file(self, path: str) -> "BuildFile":
+        existing = self.all.get(path)
+        if existing is None:
+            raise RuntimeError(f"File at path {path} not found")
+        if not isinstance(existing, BuildFile):
+            raise RuntimeError(
+                f"Entity at path {path} is not a file. It is: {existing}"
+            )
+        return existing
+
+    def write_status(self, message: str):
+        print(message, file=self.stderr)
+
+    def get_root(self, namespace: FileNamespace) -> Path:
+        return FileNamespaceToPath[namespace](self)
+
+    def analyze(self, *entrypoints: Entrypoint):
+        """Analyzes all entrypoints building the graph."""
+        for entrypoint in entrypoints:
+            if self.verbose_level > 1:
+                self.write_status(f"Analyzing entrypoint {entrypoint.name}")
+            with self.get_context("") as context:
+                entrypoint()
+
+    def build(self, *initial_deps: "BuildDependency"):
+        """Transitively builds the given deps."""
+        scheduler = Scheduler(stderr=self.stderr)
+        success = False
+        try:
+            for d in initial_deps:
+                scheduler.add_initial_dep(d)
+                scheduler.build()
+            success = True
+        finally:
+            if not success:
+                print("Waiting for background tasks to complete...", file=self.stderr)
+            scheduler.shutdown()
+
+
+class BuildDependency:
+    """Base class of entities that can act as a build dependency."""
+
+    def __init__(
+        self, *, executor: Executor, deps: set["BuildDependency"] | None = None
+    ):
+        self.executor = executor
+        self.deps: set[BuildDependency] = set()
+        if deps:
+            self.deps.update(deps)
+
+        # Scheduling state.
+        self.future: concurrent.futures.Future | None = None
+        self.start_time: float | None = None
+        self.finish_time: float | None = None
+
+    @property
+    def is_scheduled(self) -> bool:
+        return self.future is not None
+
+    @property
+    def execution_time(self) -> float:
+        if self.start_time is None:
+            return 0.0
+        if self.finish_time is None:
+            return time.time() - self.start_time
+        return self.finish_time - self.start_time
+
+    def start(self, future: concurrent.futures.Future):
+        assert not self.is_scheduled, f"Cannot start an already scheduled dep: {self}"
+        self.future = future
+        self.start_time = time.time()
+
+    def finish(self):
+        assert self.is_scheduled, "Cannot finish an unstarted dep"
+        self.finish_time = time.time()
+        self.future.set_result(self)
+
+
+class BuildFile(BuildDependency):
+    """Generated file in the build tree."""
+
+    def __init__(
+        self,
+        *,
+        executor: Executor,
+        path: str,
+        namespace: FileNamespace = FileNamespace.GEN,
+        deps: set[BuildDependency] | None = None,
+    ):
+        super().__init__(executor=executor, deps=deps)
+        self.def_stack = traceback.extract_stack()[0:-2]
+        self.executor = executor
+        self.path = path
+        self.namespace = namespace
+        # Set of build files that must be made available to any transitive user
+        # of this build file at runtime.
+        self.runfiles: set["BuildFile"] = set()
+
+        executor.check_path_not_exists(path, self)
+        executor.all[path] = self
+
+    def get_fs_path(self) -> Path:
+        path = self.executor.get_root(self.namespace) / self.path
+        path.parent.mkdir(parents=True, exist_ok=True)
+        return path
+
+    def __repr__(self):
+        return f"BuildFile[{self.namespace}]({self.path})"
+
+
+class ActionConcurrency(enum.StrEnum):
+    THREAD = enum.auto()
+    PROCESS = enum.auto()
+    NONE = enum.auto()
+
+
+class BuildAction(BuildDependency, abc.ABC):
+    """An action that must be carried out."""
+
+    def __init__(
+        self,
+        *,
+        desc: str,
+        executor: Executor,
+        concurrency: ActionConcurrency = ActionConcurrency.THREAD,
+        deps: set[BuildDependency] | None = None,
+    ):
+        super().__init__(executor=executor, deps=deps)
+        self.desc = desc
+        self.concurrnecy = concurrency
+
+    def __str__(self):
+        return self.desc
+
+    def __repr__(self):
+        return f"Action[{type(self).__name__}]('{self.desc}')"
+
+    @abc.abstractmethod
+    def invoke(self):
+        ...
+
+
+class BuildContext(BuildDependency):
+    """Manages a build graph under construction."""
+
+    def __init__(self, path: str, executor: Executor):
+        super().__init__(executor=executor)
+        self.def_stack = traceback.extract_stack()[0:-2]
+        self.executor = executor
+        self.path = path
+        executor.check_path_not_exists(path, self)
+        executor.all[path] = self
+        self.analyzed = False
+
+    def __repr__(self):
+        return f"{type(self).__name__}(path='{self.path}')"
+
+    def allocate_file(
+        self, path: str, namespace: FileNamespace = FileNamespace.GEN
+    ) -> BuildFile:
+        """Allocates a file in the build tree with local path |path|.
+
+        If |path| is absoluate (starts with '/'), then it is used as-is. Otherwise,
+        it is joined with the path of this context.
+        """
+        if not path.startswith("/"):
+            path = join_namespace(self.path, path)
+        return BuildFile(executor=self.executor, path=path, namespace=namespace)
+
+    def file(self, file: str | BuildFile) -> BuildFile:
+        """Accesses a BuildFile by either string (path) or BuildFile.
+
+        It must already exist.
+        """
+        if isinstance(file, BuildFile):
+            return file
+        path = file
+        if not path.startswith("/"):
+            path = join_namespace(self.path, path)
+        existing = self.executor.all.get(path)
+        if not isinstance(existing, BuildFile):
+            all_files = [
+                f.path for f in self.executor.all.values() if isinstance(f, BuildFile)
+            ]
+            raise RuntimeError(
+                f"File with path '{path}' is not known in the build graph. Available:\n"
+                f"  {'\n  '.join(all_files)}"
+            )
+        return existing
+
+    def files(
+        self, files: str | BuildFile | Collection[str | BuildFile]
+    ) -> list[BuildFile]:
+        """Accesses a collection of files (or single) as a list of BuildFiles."""
+        if isinstance(files, (str, BuildFile)):
+            return [self.file(files)]
+        return [self.file(f) for f in files]
+
+    @staticmethod
+    def current() -> "BuildContext":
+        try:
+            return _locals.context_stack[-1]
+        except (AttributeError, IndexError):
+            raise RuntimeError(
+                "The current code can only be evaluated within an active BuildContext"
+            )
+
+    def __enter__(self) -> "BuildContext":
+        try:
+            stack = _locals.context_stack
+        except AttributeError:
+            stack = _locals.context_stack = []
+        stack.append(self)
+        return self
+
+    def __exit__(self, *args):
+        try:
+            stack = _locals.context_stack
+        except AttributeError:
+            raise AssertionError("BuildContext exit without enter")
+        existing = stack.pop()
+        assert existing is self, "Unbalanced BuildContext enter/exit"
+
+    def populate_arg_parser(self, parser: argparse.ArgumentParser):
+        ...
+
+
+class BuildEntrypoint(BuildContext):
+    def __init__(self, path: str, executor: Executor, entrypoint: Entrypoint):
+        super().__init__(path, executor)
+        self.entrypoint = entrypoint
+        self.outputs: list[BuildFile] = []
+
+
+class Scheduler:
+    """Holds resources related to scheduling."""
+
+    def __init__(self, stderr: IO):
+        self.stderr = stderr
+
+        # Inverted producer-consumer graph nodes mapping a producer dep to
+        # all deps which directly depend on it and will be unblocked by it
+        # beins satisfied.
+        self.producer_graph: dict[BuildDependency, list[BuildDependency]] = {}
+
+        # Set of build dependencies that have been scheduled. These will all
+        # have a future set on them prior to adding to the set.
+        self.in_flight_deps: set[BuildDependency] = set()
+
+        self.thread_pool_executor = concurrent.futures.ThreadPoolExecutor(
+            max_workers=10, thread_name_prefix="iree.build"
+        )
+        self.process_pool_executor = concurrent.futures.ProcessPoolExecutor(
+            max_workers=10, mp_context=multiprocessing.get_context("spawn")
+        )
+
+    def shutdown(self):
+        self.thread_pool_executor.shutdown(cancel_futures=True)
+        self.process_pool_executor.shutdown(cancel_futures=True)
+
+    def add_initial_dep(self, initial_dep: BuildDependency):
+        assert isinstance(initial_dep, BuildDependency)
+        if initial_dep in self.producer_graph:
+            # Already in the graph.
+            return
+
+        # At this point nothing depends on this initial dep, so just note it
+        # as producing nothing.
+        self.producer_graph[initial_dep] = []
+
+        # Adds a dep requested by some top-level caller.
+        stack: set[BuildDependency] = set()
+        stack.add(initial_dep)
+        for producer_dep in initial_dep.deps:
+            self._add_dep(producer_dep, initial_dep, stack)
+
+    def _add_dep(
+        self,
+        producer_dep: BuildDependency,
+        consumer_dep: BuildDependency,
+        stack: set[BuildDependency],
+    ):
+        if producer_dep in stack:
+            raise RuntimeError(
+                f"Circular dependency: '{producer_dep}' depends on itself: {stack}"
+            )
+        plist = self.producer_graph.get(producer_dep)
+        if plist is None:
+            plist = []
+            self.producer_graph[producer_dep] = plist
+        plist.append(consumer_dep)
+        next_stack = set(stack)
+        next_stack.add(producer_dep)
+        if producer_dep.deps:
+            # Intermediate dep.
+            for next_dep in producer_dep.deps:
+                self._add_dep(next_dep, producer_dep, next_stack)
+
+    def build(self):
+        # Build all deps until the graph is satisfied.
+        # Schedule any deps that have no dependencies to start things off.
+        for eligible_dep in self.producer_graph.keys():
+            if len(eligible_dep.deps) == 0:
+                self._schedule_action(eligible_dep)
+                self.in_flight_deps.add(eligible_dep)
+
+        while self.producer_graph:
+            print(
+                f"Servicing {len(self.producer_graph)} outstanding tasks",
+                file=self.stderr,
+            )
+            self._service_graph()
+
+    def _service_graph(self):
+        completed_deps: set[BuildDependency] = set()
+        try:
+            for completed_fut in concurrent.futures.as_completed(
+                (d.future for d in self.in_flight_deps), 0
+            ):
+                completed_dep = completed_fut.result()
+                assert isinstance(completed_dep, BuildDependency)
+                print(f"Completed {completed_dep}", file=self.stderr)
+                completed_deps.add(completed_dep)
+        except TimeoutError:
+            pass
+
+        # Purge done from in-flight list.
+        self.in_flight_deps.difference_update(completed_deps)
+
+        # Schedule any available.
+        for completed_dep in completed_deps:
+            ready_list = self.producer_graph.get(completed_dep)
+            if ready_list is None:
+                continue
+            del self.producer_graph[completed_dep]
+            for ready_dep in ready_list:
+                self._schedule_action(ready_dep)
+                self.in_flight_deps.add(ready_dep)
+
+        # Do a blocking wait for at least one ready.
+        concurrent.futures.wait(
+            (d.future for d in self.in_flight_deps),
+            return_when=concurrent.futures.FIRST_COMPLETED,
+        )
+
+    def _schedule_action(self, dep: BuildDependency):
+        if dep.is_scheduled:
+            return
+        if isinstance(dep, BuildAction):
+
+            def invoke():
+                dep.invoke()
+                return dep
+
+            print(f"Scheduling action: {dep}", file=self.stderr)
+            dep.start(self.thread_pool_executor.submit(invoke))
+        else:
+            # Not schedulable. Just mark it as done.
+            dep.start(concurrent.futures.Future())
+            dep.finish()
+
+
+# Type aliases.
+BuildFileLike = BuildFile | str
diff --git a/compiler/bindings/python/iree/build/lang.py b/compiler/bindings/python/iree/build/lang.py
new file mode 100644
index 000000000000..5cb87790aec3
--- /dev/null
+++ b/compiler/bindings/python/iree/build/lang.py
@@ -0,0 +1,52 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from typing import Callable
+
+import argparse
+import functools
+
+from iree.build.executor import ClArg, Entrypoint
+
+__all__ = [
+    "cl_arg",
+    "entrypoint",
+]
+
+
+def entrypoint(
+    f=None,
+    *,
+    description: str | None = None,
+):
+    """Function decorator to turn it into a build entrypoint."""
+    if f is None:
+        return functools.partial(entrypoint, description=description)
+    target = Entrypoint(f.__name__, f, description=description)
+    functools.wraps(target, f)
+    return target
+
+
+def cl_arg(name: str, *, action=None, default=None, type=None, help=None):
+    """Used to define or reference a command-line argument from within actions
+    and entry-points.
+
+    Keywords have the same interpretation as `ArgumentParser.add_argument()`.
+
+    Any ClArg set as a default value for an argument to an `entrypoint` will be
+    added to the global argument parser. Any particular argument name can only be
+    registered once and must not conflict with a built-in command line option.
+    The implication of this is that for single-use arguments, the `=cl_arg(...)`
+    can just be added as a default argument. Otherwise, for shared arguments,
+    it should be created at the module level and referenced.
+
+    When called, any entrypoint arguments that do not have an explicit keyword
+    set will get their value from the command line environment.
+    """
+    if name.startswith("-"):
+        raise ValueError("cl_arg name must not be prefixed with dashes")
+    dest = name.replace("-", "_")
+    return ClArg(name, action=action, default=default, type=type, dest=dest, help=help)
diff --git a/compiler/bindings/python/iree/build/net_actions.py b/compiler/bindings/python/iree/build/net_actions.py
new file mode 100644
index 000000000000..1d2e1587e63a
--- /dev/null
+++ b/compiler/bindings/python/iree/build/net_actions.py
@@ -0,0 +1,39 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+import urllib.error
+import urllib.request
+
+from iree.build.executor import BuildAction, BuildContext, BuildFile
+
+__all__ = [
+    "fetch_http",
+]
+
+
+def fetch_http(*, name: str, url: str) -> BuildFile:
+    context = BuildContext.current()
+    output_file = context.allocate_file(name)
+    action = FetchHttpAction(
+        url=url, output_file=output_file, desc=f"Fetch {url}", executor=context.executor
+    )
+    output_file.deps.add(action)
+    return output_file
+
+
+class FetchHttpAction(BuildAction):
+    def __init__(self, url: str, output_file: BuildFile, **kwargs):
+        super().__init__(**kwargs)
+        self.url = url
+        self.output_file = output_file
+
+    def invoke(self):
+        path = self.output_file.get_fs_path()
+        self.executor.write_status(f"Fetching URL: {self.url} -> {path}")
+        try:
+            urllib.request.urlretrieve(self.url, str(path))
+        except urllib.error.HTTPError as e:
+            raise IOError(f"Failed to fetch URL '{self.url}': {e}") from None
diff --git a/compiler/bindings/python/iree/build/onnx_actions.py b/compiler/bindings/python/iree/build/onnx_actions.py
new file mode 100644
index 000000000000..522089006116
--- /dev/null
+++ b/compiler/bindings/python/iree/build/onnx_actions.py
@@ -0,0 +1,90 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from iree.build.executor import BuildAction, BuildContext, BuildFile, BuildFileLike
+
+__all__ = [
+    "onnx_import",
+]
+
+
+def onnx_import(
+    *,
+    # Name of the rule and output of the final artifact.
+    name: str,
+    # Source onnx file.
+    source: BuildFileLike,
+    upgrade: bool = True,
+) -> BuildFile:
+    context = BuildContext.current()
+    input_file = context.file(source)
+    output_file = context.allocate_file(name)
+
+    # Chain through an upgrade if requested.
+    if upgrade:
+        processed_file = context.allocate_file(f"{name}__upgrade.onnx")
+        UpgradeOnnxAction(
+            input_file=input_file,
+            output_file=processed_file,
+            executor=context.executor,
+            desc=f"Upgrading ONNX {name}",
+            deps=[
+                input_file,
+            ],
+        )
+        input_file = processed_file
+
+    # Import.
+    ImportOnnxAction(
+        input_file=input_file,
+        output_file=output_file,
+        desc=f"Importing ONNX {name}",
+        executor=context.executor,
+        deps=[
+            input_file,
+        ],
+    )
+
+    output_file.deps.add(processed_file)
+    return output_file
+
+
+class UpgradeOnnxAction(BuildAction):
+    def __init__(self, input_file: BuildFile, output_file: BuildFile, **kwargs):
+        super().__init__(**kwargs)
+        self.input_file = input_file
+        self.output_file = output_file
+        output_file.deps.add(self)
+
+    def invoke(self):
+        import onnx
+
+        input_path = self.input_file.get_fs_path()
+        output_path = self.output_file.get_fs_path()
+
+        original_model = onnx.load_model(str(input_path))
+        converted_model = onnx.version_converter.convert_version(original_model, 17)
+        onnx.save(converted_model, str(output_path))
+
+
+class ImportOnnxAction(BuildAction):
+    def __init__(self, input_file: BuildFile, output_file: BuildFile, **kwargs):
+        super().__init__(**kwargs)
+        self.input_file = input_file
+        self.output_file = output_file
+        output_file.deps.add(self)
+
+    def invoke(self):
+        import iree.compiler.tools.import_onnx.__main__ as m
+
+        args = m.parse_arguments(
+            [
+                str(self.input_file.get_fs_path()),
+                "-o",
+                str(self.output_file.get_fs_path()),
+            ]
+        )
+        m.main(args)
diff --git a/compiler/bindings/python/test/CMakeLists.txt b/compiler/bindings/python/test/CMakeLists.txt
index 6f6cdb913de9..ca809a8016c4 100644
--- a/compiler/bindings/python/test/CMakeLists.txt
+++ b/compiler/bindings/python/test/CMakeLists.txt
@@ -5,6 +5,7 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 add_subdirectory(api)
+add_subdirectory(build_api)
 add_subdirectory(extras)
 add_subdirectory(ir)
 add_subdirectory(tools)
diff --git a/compiler/bindings/python/test/build_api/CMakeLists.txt b/compiler/bindings/python/test/build_api/CMakeLists.txt
new file mode 100644
index 000000000000..b8bd81759ddc
--- /dev/null
+++ b/compiler/bindings/python/test/build_api/CMakeLists.txt
@@ -0,0 +1,15 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+# The mnist builder depends on onnx, which needs the torch input support.
+if(IREE_INPUT_TORCH)
+  iree_py_test(
+    NAME
+      mnist_builder_test
+    SRCS
+      "mnist_builder_test.py"
+  )
+endif()
diff --git a/compiler/bindings/python/test/build_api/mnist_builder.py b/compiler/bindings/python/test/build_api/mnist_builder.py
new file mode 100644
index 000000000000..54d6e3064693
--- /dev/null
+++ b/compiler/bindings/python/test/build_api/mnist_builder.py
@@ -0,0 +1,30 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from iree.build import *
+
+
+@entrypoint(description="Compiles an mnist model")
+def mnist(
+    url=cl_arg(
+        "mnist-onnx-url",
+        default="https://github.com/onnx/models/raw/main/validated/vision/classification/mnist/model/mnist-12.onnx",
+        help="URL from which to download mnist",
+    ),
+):
+    fetch_http(
+        name="mnist.onnx",
+        url=url,
+    )
+    onnx_import(
+        name="mnist.mlir",
+        source="mnist.onnx",
+    )
+    return "mnist.mlir"
+
+
+if __name__ == "__main__":
+    iree_build_main()
diff --git a/compiler/bindings/python/test/build_api/mnist_builder_test.py b/compiler/bindings/python/test/build_api/mnist_builder_test.py
new file mode 100644
index 000000000000..02a914025882
--- /dev/null
+++ b/compiler/bindings/python/test/build_api/mnist_builder_test.py
@@ -0,0 +1,108 @@
+# Copyright 2024 The IREE Authors
+#
+# Licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+import io
+from pathlib import Path
+import re
+import subprocess
+import unittest
+import tempfile
+import sys
+
+from iree.build import *
+
+THIS_DIR = Path(__file__).resolve().parent
+
+
+class MnistBuilderTest(unittest.TestCase):
+    def setUp(self):
+        self._temp_dir = tempfile.TemporaryDirectory(ignore_cleanup_errors=True)
+        self._temp_dir.__enter__()
+        self.output_path = Path(self._temp_dir.name)
+
+    def tearDown(self) -> None:
+        self._temp_dir.__exit__(None, None, None)
+
+    # Tests that invoking via the tool works:
+    #   python -m iree.build {path to py file}
+    # We execute this out of process in order to verify the full flow.
+    def testBuildEntrypoint(self):
+        output = subprocess.check_output(
+            [
+                sys.executable,
+                "-m",
+                "iree.build",
+                str(THIS_DIR / "mnist_builder.py"),
+                "--output-dir",
+                str(self.output_path),
+            ]
+        ).decode()
+        print("OUTPUT:", output)
+        output_paths = output.splitlines()
+        self.assertEqual(len(output_paths), 1)
+        output_path = Path(output_paths[0])
+        self.assertTrue(output_path.is_relative_to(self.output_path))
+        contents = output_path.read_text()
+        self.assertIn("module", contents)
+
+    # Tests that invoking via the build module itself works
+    #   python {path to py file}
+    # We execute this out of process in order to verify the full flow.
+    def testTargetModuleEntrypoint(self):
+        output = subprocess.check_output(
+            [
+                sys.executable,
+                str(THIS_DIR / "mnist_builder.py"),
+                "--output-dir",
+                str(self.output_path),
+            ]
+        ).decode()
+        print("OUTPUT:", output)
+        output_paths = output.splitlines()
+        self.assertEqual(len(output_paths), 1)
+
+    def testListCommand(self):
+        mod = load_build_module(THIS_DIR / "mnist_builder.py")
+        out_file = io.StringIO()
+        iree_build_main(mod, args=["--list"], stdout=out_file)
+        output = out_file.getvalue().strip()
+        self.assertEqual(output, "mnist")
+
+    def testListAllCommand(self):
+        mod = load_build_module(THIS_DIR / "mnist_builder.py")
+        out_file = io.StringIO()
+        iree_build_main(mod, args=["--list-all"], stdout=out_file)
+        output = out_file.getvalue().splitlines()
+        self.assertIn("mnist", output)
+        self.assertIn("mnist/mnist.onnx", output)
+
+    def testActionCLArg(self):
+        mod = load_build_module(THIS_DIR / "mnist_builder.py")
+        out_file = io.StringIO()
+        err_file = io.StringIO()
+        with self.assertRaisesRegex(
+            IOError,
+            re.escape("Failed to fetch URL 'https://github.com/iree-org/doesnotexist'"),
+        ):
+            iree_build_main(
+                mod,
+                args=[
+                    "--mnist-onnx-url",
+                    "https://github.com/iree-org/doesnotexist",
+                ],
+                stdout=out_file,
+                stderr=err_file,
+            )
+
+
+if __name__ == "__main__":
+    try:
+        import onnx
+    except ModuleNotFoundError:
+        print(f"Skipping test {__file__} because Python dependency `onnx` is not found")
+        sys.exit(0)
+
+    unittest.main()
diff --git a/compiler/setup.py b/compiler/setup.py
index 8204e820e251..bf5d734a2a88 100644
--- a/compiler/setup.py
+++ b/compiler/setup.py
@@ -454,6 +454,7 @@ def find_git_submodule_revision(submodule_path):
     packages=packages,
     entry_points={
         "console_scripts": [
+            "iree-build = iree.build.__main__:main",
             "iree-compile = iree.compiler.tools.scripts.iree_compile.__main__:main",
             "iree-import-onnx = iree.compiler.tools.import_onnx.__main__:_cli_main",
             "iree-ir-tool = iree.compiler.tools.ir_tool.__main__:_cli_main",