diff --git a/.strict-typing b/.strict-typing
index 67d7866ba62..db30bfb3494 100644
--- a/.strict-typing
+++ b/.strict-typing
@@ -141,6 +141,7 @@ homeassistant.components.dlna_dmr.*
 homeassistant.components.dnsip.*
 homeassistant.components.doorbird.*
 homeassistant.components.dormakaba_dkey.*
+homeassistant.components.downloader.*
 homeassistant.components.dsmr.*
 homeassistant.components.dunehd.*
 homeassistant.components.efergy.*
diff --git a/homeassistant/components/downloader/__init__.py b/homeassistant/components/downloader/__init__.py
index 9aca80b04da..1922fde3102 100644
--- a/homeassistant/components/downloader/__init__.py
+++ b/homeassistant/components/downloader/__init__.py
@@ -1,4 +1,6 @@
 """Support for functionality to download files."""
+from __future__ import annotations
+
 from http import HTTPStatus
 import logging
 import os
@@ -61,7 +63,7 @@ def setup(hass: HomeAssistant, config: ConfigType) -> bool:
     def download_file(service: ServiceCall) -> None:
         """Start thread to download file specified in the URL."""
 
-        def do_download():
+        def do_download() -> None:
             """Download the file."""
             try:
                 url = service.data[ATTR_URL]
diff --git a/mypy.ini b/mypy.ini
index 8d621949810..e5326bf16af 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -1171,6 +1171,16 @@ disallow_untyped_defs = true
 warn_return_any = true
 warn_unreachable = true
 
+[mypy-homeassistant.components.downloader.*]
+check_untyped_defs = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+warn_return_any = true
+warn_unreachable = true
+
 [mypy-homeassistant.components.dsmr.*]
 check_untyped_defs = true
 disallow_incomplete_defs = true