diff --git a/homeassistant/bootstrap.py b/homeassistant/bootstrap.py
index 81d0fa72134..939d3073f57 100644
--- a/homeassistant/bootstrap.py
+++ b/homeassistant/bootstrap.py
@@ -285,7 +285,9 @@ def async_enable_logging(
 
     This method must be run in the event loop.
     """
-    fmt = "%(asctime)s %(levelname)s (%(threadName)s) [%(name)s] %(message)s"
+    fmt = (
+        "%(asctime)s.%(msecs)03d %(levelname)s (%(threadName)s) [%(name)s] %(message)s"
+    )
     datefmt = "%Y-%m-%d %H:%M:%S"
 
     if not log_no_color: