diff --git a/MANIFEST.in b/MANIFEST.in
new file mode 100644
index 00000000..50d942e6
--- /dev/null
+++ b/MANIFEST.in
@@ -0,0 +1 @@
+recursive-include a_sync *.pxd
\ No newline at end of file
diff --git a/setup.py b/setup.py
index 0b5ee3bf..843f0198 100644
--- a/setup.py
+++ b/setup.py
@@ -22,8 +22,9 @@
     setup_requires=["setuptools_scm", "cython"],
     python_requires=">=3.8,<3.13",
     package_data={
-        "a_sync": ["py.typed"],
+        "a_sync": ["py.typed", "*.pxd", "**/*.pxd"],
     },
+    include_package_data=True,
     ext_modules=cythonize(
         "a_sync/**/*.pyx",
         compiler_directives={