diff --git a/CMakeLists.txt b/CMakeLists.txt
index 522df1c3..93c9c56d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -215,6 +215,10 @@ if(WEBP_BUILD_CWEBP)
   install(TARGETS cwebp RUNTIME DESTINATION bin)
 endif()
 
+if(WEBP_BUILD_GIF2WEBP AND NOT GIF_FOUND)
+  unset(WEBP_BUILD_GIF2WEBP CACHE)
+endif()
+
 if(WEBP_BUILD_GIF2WEBP OR WEBP_BUILD_IMG2WEBP)
   parse_Makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/mux "WEBP_MUX_SRCS"
     "")