diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index b2832fd3b3..24b714b0e7 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -112,7 +112,7 @@ UNIFY_ENVVARS_AND_CACHE(LIBXML2_LIBRARIES)
 UNIFY_ENVVARS_AND_CACHE(PCRE_LIBRARY_DIR)
 UNIFY_ENVVARS_AND_CACHE(PYTHON_EXECUTABLE)
 
-if (GLTF_SUPPORT)
+if (GLTF_SUPPORT AND BUILD_CONVERT)
 UNIFY_ENVVARS_AND_CACHE(JSON_INCLUDE_DIR)
 FIND_FILE(json_hpp "json.hpp" ${JSON_INCLUDE_DIR}/nlohmann)
 IF(json_hpp)