diff --git a/protobuf.pc.in b/protobuf.pc.in
index 282fef35b2..4e88b514a2 100644
--- a/protobuf.pc.in
+++ b/protobuf.pc.in
@@ -8,5 +8,5 @@ Description: Google's Data Interchange Format
 Version: @VERSION@
 Libs: -L${libdir} -lprotobuf @PTHREAD_LIBS@
 Libs.private: @LIBS@
-Cflags: -I${includedir} @PTHREAD_CFLAGS@ @CXXFLAGS@
+Cflags: -I${includedir} @PTHREAD_CFLAGS@
 Conflicts: protobuf-lite