diff --git a/mypy/main.py b/mypy/main.py
index 3f25ced16106..539fe912d1da 100644
--- a/mypy/main.py
+++ b/mypy/main.py
@@ -802,7 +802,7 @@ def add_invertible_flag(
     add_invertible_flag(
         "--warn-unreachable",
         default=False,
-        strict_flag=False,
+        strict_flag=True,
         help="Warn about statements or expressions inferred to be unreachable",
         group=lint_group,
     )