diff --git a/core/CMakeLists.txt b/core/CMakeLists.txt
index 581d00b..336f170 100644
--- a/core/CMakeLists.txt
+++ b/core/CMakeLists.txt
@@ -135,7 +135,9 @@ else()
 endif ()
 
 # common test executable
-add_subdirectory(testlib)
+if(BUILD_TESTING)
+  add_subdirectory(testlib)
+endif()
 
 # Tests that check and output the vxl configuration
 # NOTE: some external projects remove the tests directory (aka ITK)