diff --git a/CMakeLists.txt b/CMakeLists.txt
index 108ef11..c17bf52 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,6 +19,7 @@ find_package(nlohmann_json)
 if(NOT nlohmann_json_FOUND)
     message(STATUS "nlohmann_json not found on system, fetching from GitHub")
 
+    include(FetchContent)
     FetchContent_Declare(
         nlohmann_json
         GIT_REPOSITORY https://github.com/nlohmann/json