diff --git a/README.md b/README.md
index 7e96c4df..4b0b0c9c 100644
--- a/README.md
+++ b/README.md
@@ -2,8 +2,8 @@
 
 This is a small wrapper around common array libraries that is compatible with
 the [Array API standard](https://data-apis.org/array-api/latest/). Currently,
-NumPy, CuPy, PyTorch, Dask, JAX and `sparse` are supported. If you want support
-for other array libraries, or if you encounter any issues, please [open an
-issue](https://github.com/data-apis/array-api-compat/issues).
+NumPy, CuPy, PyTorch, Dask, JAX, ndonnx and `sparse` are supported. If you want
+support for other array libraries, or if you encounter any issues, please [open
+an issue](https://github.com/data-apis/array-api-compat/issues).
 
 See the documentation for more details https://data-apis.org/array-api-compat/
diff --git a/array_api_compat/common/_helpers.py b/array_api_compat/common/_helpers.py
index 32fb0e70..b55b16e2 100644
--- a/array_api_compat/common/_helpers.py
+++ b/array_api_compat/common/_helpers.py
@@ -48,6 +48,7 @@ def is_numpy_array(x):
     is_array_api_obj
     is_cupy_array
     is_torch_array
+    is_ndonnx_array
     is_dask_array
     is_jax_array
     is_pydata_sparse_array
@@ -78,11 +79,12 @@ def is_cupy_array(x):
     is_array_api_obj
     is_numpy_array
     is_torch_array
+    is_ndonnx_array
     is_dask_array
     is_jax_array
     is_pydata_sparse_array
     """
-    # Avoid importing NumPy if it isn't already
+    # Avoid importing CuPy if it isn't already
     if 'cupy' not in sys.modules:
         return False
 
@@ -118,6 +120,33 @@ def is_torch_array(x):
     # TODO: Should we reject ndarray subclasses?
     return isinstance(x, torch.Tensor)
 
+def is_ndonnx_array(x):
+    """
+    Return True if `x` is a ndonnx Array.
+
+    This function does not import ndonnx if it has not already been imported
+    and is therefore cheap to use.
+
+    See Also
+    --------
+
+    array_namespace
+    is_array_api_obj
+    is_numpy_array
+    is_cupy_array
+    is_ndonnx_array
+    is_dask_array
+    is_jax_array
+    is_pydata_sparse_array
+    """
+    # Avoid importing torch if it isn't already
+    if 'ndonnx' not in sys.modules:
+        return False
+
+    import ndonnx as ndx
+
+    return isinstance(x, ndx.Array)  
+
 def is_dask_array(x):
     """
     Return True if `x` is a dask.array Array.
@@ -133,6 +162,7 @@ def is_dask_array(x):
     is_numpy_array
     is_cupy_array
     is_torch_array
+    is_ndonnx_array
     is_jax_array
     is_pydata_sparse_array
     """
@@ -160,6 +190,7 @@ def is_jax_array(x):
     is_numpy_array
     is_cupy_array
     is_torch_array
+    is_ndonnx_array
     is_dask_array
     is_pydata_sparse_array
     """
@@ -188,6 +219,7 @@ def is_pydata_sparse_array(x) -> bool:
     is_numpy_array
     is_cupy_array
     is_torch_array
+    is_ndonnx_array
     is_dask_array
     is_jax_array
     """
@@ -211,6 +243,7 @@ def is_array_api_obj(x):
     is_numpy_array
     is_cupy_array
     is_torch_array
+    is_ndonnx_array
     is_dask_array
     is_jax_array
     """
@@ -613,6 +646,7 @@ def size(x):
     "is_jax_array",
     "is_numpy_array",
     "is_torch_array",
+    "is_ndonnx_array",
     "is_pydata_sparse_array",
     "size",
     "to_device",
diff --git a/requirements-dev.txt b/requirements-dev.txt
index d06de300..c9d10f71 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -5,3 +5,4 @@ numpy
 pytest
 torch
 sparse >=0.15.1
+ndonnx