diff --git a/Makefile.am b/Makefile.am
index a2e49fdc5e66..ddbe08b2f051 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -827,6 +827,7 @@ php_EXTRA_DIST=                                                       \
   php/ext/google/protobuf/wkt.inc                                     \
   php/generate_descriptor_protos.sh                                   \
   php/generate_test_protos.sh                                         \
+  php/prepare_c_extension.sh                                          \
   php/release.sh                                                      \
   php/src/GPBMetadata/Google/Protobuf/Any.php                         \
   php/src/GPBMetadata/Google/Protobuf/Api.php                         \