diff --git a/esphome/components/sensor/__init__.py b/esphome/components/sensor/__init__.py
index ebd4fcc26c..26ddac3464 100644
--- a/esphome/components/sensor/__init__.py
+++ b/esphome/components/sensor/__init__.py
@@ -258,11 +258,11 @@ def sensor_schema(
                 ): validate_last_reset_type
             }
         )
-    if last_reset_type_ != LAST_RESET_TYPE_NONE:
+    if last_reset_type != LAST_RESET_TYPE_NONE:
         schema = schema.extend(
             {
                 cv.Optional(
-                    CONF_LAST_RESET_TYPE, default=last_reset_type_
+                    CONF_LAST_RESET_TYPE, default=last_reset_type
                 ): validate_last_reset_type
             }
         )