diff --git a/Makefile b/Makefile
index 58bbc7a..3794d94 100644
--- a/Makefile
+++ b/Makefile
@@ -2978,6 +2978,7 @@
     src/cpp/util/time.cc \
 
 PUBLIC_HEADERS_CXX += \
+    include/grpc++/async_unary_call.h \
     include/grpc++/channel_arguments.h \
     include/grpc++/channel_interface.h \
     include/grpc++/client_context.h \