diff --git a/ruby/ext/google/protobuf_c/extconf.rb b/ruby/ext/google/protobuf_c/extconf.rb
index ec17787f79fd..eaab4db74f30 100755
--- a/ruby/ext/google/protobuf_c/extconf.rb
+++ b/ruby/ext/google/protobuf_c/extconf.rb
@@ -17,4 +17,5 @@
 $objs = ["protobuf.o", "convert.o", "defs.o", "message.o",
          "repeated_field.o", "map.o", "ruby-upb.o", "wrap_memcpy.o"]
 
+find_header('third_party/wyhash/wyhash.h', '../../../..')
 create_makefile("google/protobuf_c")