diff --git a/esphome/__main__.py b/esphome/__main__.py
index 75f06fb9fe..b8e1055b70 100644
--- a/esphome/__main__.py
+++ b/esphome/__main__.py
@@ -526,7 +526,7 @@ def compile_program(args: ArgsProtocol, config: ConfigType) -> int:
     return 0 if idedata is not None else 1
 
 
-def _check_and_emit_buildinfo():
+def _check_and_emit_buildinfo() -> None:
     """Check if firmware was rebuilt and emit buildinfo."""
     import json