diff --git a/include/mapnik/webp_io.hpp b/include/mapnik/webp_io.hpp
index 6f8ed2e18..1e1ccc2e8 100644
--- a/include/mapnik/webp_io.hpp
+++ b/include/mapnik/webp_io.hpp
@@ -24,6 +24,7 @@
 #define MAPNIK_WEBP_IO_HPP
 
 // mapnik
+#include <mapnik/image_data.hpp>
 #include <mapnik/util/conversions.hpp>
 
 // webp