diff --git a/build_ext.py b/build_ext.py
index df80aa32..4c5e5486 100644
--- a/build_ext.py
+++ b/build_ext.py
@@ -37,6 +37,9 @@ def build(setup_kwargs):
                 cmdclass=dict(build_ext=BuildExt),
             )
         )
+        setup_kwargs["exclude_package_data"] = {
+            pkg: ["*.c"] for pkg in setup_kwargs["packages"]
+        }
     except Exception:
         if os.environ.get("REQUIRE_CYTHON"):
             raise