diff --git a/External/CMakeLists.txt b/External/CMakeLists.txt
index 4d9690134a..6ff4f47acd 100644
--- a/External/CMakeLists.txt
+++ b/External/CMakeLists.txt
@@ -10,7 +10,8 @@ if(BUILD_TESTING)
         if(WIN32)
             set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
         endif(WIN32)
-        add_subdirectory(googletest)
+        # EXCLUDE_FROM_ALL keeps the install target from installing GTEST files.
+        add_subdirectory(googletest EXCLUDE_FROM_ALL)
         set(GTEST_TARGETS
             gtest
             gtest_main