diff --git a/3rdparty/CMakeLists.txt b/3rdparty/CMakeLists.txt
index 6b4425b..ad35ca6 100644
--- a/3rdparty/CMakeLists.txt
+++ b/3rdparty/CMakeLists.txt
@@ -1,4 +1,4 @@
 if(NOT KIMA2_USE_EXTERNAL_JSON)
   set(JSON_BuildTests OFF CACHE INTERNAL "")
-  add_subdirectory(nlohmann_json)
+  add_subdirectory(nlohmann_json EXCLUDE_FROM_ALL)
 endif()