diff --git a/extras/CatchAddTests.cmake b/extras/CatchAddTests.cmake
index ea3fec59..5c67c874 100644
--- a/extras/CatchAddTests.cmake
+++ b/extras/CatchAddTests.cmake
@@ -114,6 +114,7 @@ function(catch_discover_tests_impl)
       --list-tests
       --reporter json
       --out "${listing_output_path}"
+      --order lex # Make sure the output order, and thus test registration order, is consistent across runs.
     OUTPUT_VARIABLE listing_output
     RESULT_VARIABLE result
     WORKING_DIRECTORY "${_TEST_WORKING_DIR}"