diff --git a/official/recommendation/ncf_main.py b/official/recommendation/ncf_main.py
index ded3cb7c2e9fe3ae61a8bf61aecd764258e8ade1..2ea55a3e66bcb005a06a00a0c88c13b0489440a0 100644
--- a/official/recommendation/ncf_main.py
+++ b/official/recommendation/ncf_main.py
@@ -403,7 +403,7 @@ def define_ncf_flags():
           "achieved by MLPerf implementation."))
 
   flags.DEFINE_bool(
-      name="ml_perf", default=None,
+      name="ml_perf", default=False,
       help=flags_core.help_wrap(
           "If set, changes the behavior of the model slightly to match the "
           "MLPerf reference implementations here: \n"