diff --git a/homeassistant/components/diagnostics/__init__.py b/homeassistant/components/diagnostics/__init__.py
index 481c02bad68..1c65b49fe0f 100644
--- a/homeassistant/components/diagnostics/__init__.py
+++ b/homeassistant/components/diagnostics/__init__.py
@@ -23,7 +23,11 @@ from homeassistant.helpers.json import (
 )
 from homeassistant.helpers.system_info import async_get_system_info
 from homeassistant.helpers.typing import ConfigType
-from homeassistant.loader import async_get_custom_components, async_get_integration
+from homeassistant.loader import (
+    Manifest,
+    async_get_custom_components,
+    async_get_integration,
+)
 from homeassistant.setup import async_get_domain_setup_times
 from homeassistant.util.json import format_unserializable_data
 
@@ -157,6 +161,23 @@ def handle_get(
     )
 
 
+@callback
+def async_format_manifest(manifest: Manifest) -> Manifest:
+    """Format manifest for diagnostics.
+
+    Remove the @ from codeowners so that
+    when users download the diagnostics and paste
+    the codeowners into the repository, it will
+    not notify the users in the codeowners file.
+    """
+    manifest_copy = manifest.copy()
+    if "codeowners" in manifest_copy:
+        manifest_copy["codeowners"] = [
+            codeowner.lstrip("@") for codeowner in manifest_copy["codeowners"]
+        ]
+    return manifest_copy
+
+
 async def _async_get_json_file_response(
     hass: HomeAssistant,
     data: Mapping[str, Any],
@@ -182,7 +203,7 @@ async def _async_get_json_file_response(
     payload = {
         "home_assistant": hass_sys_info,
         "custom_components": custom_components,
-        "integration_manifest": integration.manifest,
+        "integration_manifest": async_format_manifest(integration.manifest),
         "setup_times": async_get_domain_setup_times(hass, domain),
         "data": data,
     }
diff --git a/tests/components/diagnostics/test_init.py b/tests/components/diagnostics/test_init.py
index 5704131aa23..85f0b8fe788 100644
--- a/tests/components/diagnostics/test_init.py
+++ b/tests/components/diagnostics/test_init.py
@@ -1,7 +1,7 @@
 """Test the Diagnostics integration."""
 
 from http import HTTPStatus
-from unittest.mock import AsyncMock, Mock
+from unittest.mock import AsyncMock, Mock, patch
 
 import pytest
 
@@ -9,6 +9,7 @@ from homeassistant.components.websocket_api.const import TYPE_RESULT
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.device_registry import async_get
 from homeassistant.helpers.system_info import async_get_system_info
+from homeassistant.loader import async_get_integration
 from homeassistant.setup import async_setup_component
 
 from . import _get_diagnostics_for_config_entry, _get_diagnostics_for_device
@@ -90,8 +91,14 @@ async def test_download_diagnostics(
     hass_sys_info = await async_get_system_info(hass)
     hass_sys_info["run_as_root"] = hass_sys_info["user"] == "root"
     del hass_sys_info["user"]
-
-    assert await _get_diagnostics_for_config_entry(hass, hass_client, config_entry) == {
+    integration = await async_get_integration(hass, "fake_integration")
+    original_manifest = integration.manifest.copy()
+    original_manifest["codeowners"] = ["@test"]
+    with patch.object(integration, "manifest", original_manifest):
+        response = await _get_diagnostics_for_config_entry(
+            hass, hass_client, config_entry
+        )
+    assert response == {
         "home_assistant": hass_sys_info,
         "setup_times": {},
         "custom_components": {
@@ -162,7 +169,7 @@ async def test_download_diagnostics(
             },
         },
         "integration_manifest": {
-            "codeowners": [],
+            "codeowners": ["test"],
             "dependencies": [],
             "domain": "fake_integration",
             "is_built_in": True,