diff --git a/homeassistant/components/esphome/light.py b/homeassistant/components/esphome/light.py
index e455d5581d1..1205521706e 100644
--- a/homeassistant/components/esphome/light.py
+++ b/homeassistant/components/esphome/light.py
@@ -74,7 +74,7 @@ class EsphomeLight(EsphomeEntity, Light):
             red, green, blue = color_util.color_hsv_to_RGB(hue, sat, 100)
             data["rgb"] = (red / 255, green / 255, blue / 255)
         if ATTR_FLASH in kwargs:
-            data["flash"] = FLASH_LENGTHS[kwargs[ATTR_FLASH]]
+            data["flash_length"] = FLASH_LENGTHS[kwargs[ATTR_FLASH]]
         if ATTR_TRANSITION in kwargs:
             data["transition_length"] = kwargs[ATTR_TRANSITION]
         if ATTR_BRIGHTNESS in kwargs: