diff --git a/binaryen.gemspec b/binaryen.gemspec
index 4bc7d60..140aa89 100644
--- a/binaryen.gemspec
+++ b/binaryen.gemspec
@@ -15,5 +15,4 @@ Gem::Specification.new do |spec|
   spec.homepage = "https://github.com/Shopify/binaryen-rb"
   spec.platform = Gem::Platform::RUBY
   spec.extensions = ["extconf.rb"]
-  spec.add_dependency("posix-spawn", "~> 0.3.15")
 end
diff --git a/lib/binaryen/command.rb b/lib/binaryen/command.rb
index b427876..83aba3a 100644
--- a/lib/binaryen/command.rb
+++ b/lib/binaryen/command.rb
@@ -1,12 +1,10 @@
 # frozen_string_literal: true
 
-require "posix/spawn"
 require "timeout"
 require "tempfile"
 
 module Binaryen
   class Command
-    include POSIX::Spawn
     DEFAULT_MAX_OUTPUT_SIZE = 256 * 1024 * 1024 * 1024 # 256 MiB
     DEFAULT_TIMEOUT = 10
     DEFAULT_ARGS_FOR_COMMAND = {}.freeze
@@ -44,7 +42,7 @@ def spawn_command(*args, stderr: nil, stdin: nil)
 
           File.open(File::NULL, "w") do |devnull|
             IO.pipe do |err_read, err_write|
-              pid = POSIX::Spawn.pspawn(
+              pid = Process.spawn(
                 *args,
                 "--output=#{tmpfile.path}",
                 in_write.path,