diff --git a/test/subset/CMakeLists.txt b/test/subset/CMakeLists.txt
index 0a1e8f953..6fe377e14 100644
--- a/test/subset/CMakeLists.txt
+++ b/test/subset/CMakeLists.txt
@@ -2,8 +2,9 @@ if (HB_BUILD_UTILS)
   file (READ "${CMAKE_CURRENT_SOURCE_DIR}/data/Makefile.sources" SOURCES)
   extract_make_variable (TESTS ${SOURCES})
   foreach (test IN ITEMS ${TESTS})
-    add_test (NAME ${test}
-      COMMAND python run-tests.py $<TARGET_FILE:hb-subset> "data/${test}"
-      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+# TODO(grieger): Re-enable once ttx is available in CI environments.
+#    add_test (NAME ${test}
+#      COMMAND python run-tests.py $<TARGET_FILE:hb-subset> "data/${test}"
+#      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
   endforeach ()
 endif ()