diff --git a/README.rst b/README.rst
index 3d7d1a2..ccc8cfb 100644
--- a/README.rst
+++ b/README.rst
@@ -199,6 +199,8 @@ GitHub Apps
 
 GitHub Apps are ideal for organization backups in CI/CD. Tokens are scoped to specific repositories and expire after 1 hour.
 
+For a user account (no ``--organization``), ``--as-app`` lists the repositories the installation can access, so private repositories are included.
+
 **One-time setup:**
 
 1. Create a GitHub App at *Settings -> Developer Settings -> GitHub Apps -> New GitHub App*
diff --git a/github_backup/github_backup.py b/github_backup/github_backup.py
index 9a2b7d4..a8297c9 100644
--- a/github_backup/github_backup.py
+++ b/github_backup/github_backup.py
@@ -1838,6 +1838,11 @@ def retrieve_repositories(args, authenticated_user):
     if args.user == authenticated_user["login"]:
         # we must use the /user/repos API to be able to access private repos
         template = "https://{0}/user/repos".format(get_github_api_host(args))
+    elif args.as_app and not args.organization:
+        # /users/{user}/repos is public-only; the installation sees private repos too
+        template = "https://{0}/installation/repositories".format(
+            get_github_api_host(args)
+        )
     else:
         if args.private and not args.organization:
             logger.warning(
@@ -1868,6 +1873,10 @@ def retrieve_repositories(args, authenticated_user):
             logger.warning(f"Legal notice: {e.legal_url}")
         return []
 
+    if template.endswith("/installation/repositories"):
+        # Each page is {"total_count": ..., "repositories": [...]}
+        repos = [repo for page in repos for repo in page["repositories"]]
+
     return retrieve_additional_repositories(args, authenticated_user, repos)
 
 
diff --git a/tests/test_app_repositories.py b/tests/test_app_repositories.py
new file mode 100644
index 0000000..24d3411
--- /dev/null
+++ b/tests/test_app_repositories.py
@@ -0,0 +1,71 @@
+"""Tests for listing a user's repositories with a GitHub App installation token."""
+
+from unittest.mock import patch
+
+import pytest
+
+from github_backup import github_backup
+
+NO_USER = {"login": None}
+
+
+def page(*names):
+    return {
+        "total_count": 3,
+        "repositories": [{"name": name, "private": True} for name in names],
+    }
+
+
+@pytest.fixture
+def mock_retrieve_data():
+    with patch("github_backup.github_backup.retrieve_data") as mock:
+        yield mock
+
+
+def test_app_lists_user_repositories_from_installation(create_args, mock_retrieve_data):
+    args = create_args(as_app=True, include_repository=True)
+    mock_retrieve_data.return_value = [page("a", "b"), page("c")]
+
+    repos = github_backup.retrieve_repositories(args, NO_USER)
+
+    assert mock_retrieve_data.call_args.args[1] == (
+        "https://api.github.com/installation/repositories"
+    )
+    assert [r["name"] for r in repos] == ["a", "b", "c"]
+
+
+def test_app_installation_listing_uses_ghes_host(create_args, mock_retrieve_data):
+    args = create_args(
+        as_app=True, include_repository=True, github_host="ghe.example.com"
+    )
+    mock_retrieve_data.return_value = [page("a")]
+
+    github_backup.retrieve_repositories(args, NO_USER)
+
+    assert mock_retrieve_data.call_args.args[1] == (
+        "https://ghe.example.com/api/v3/installation/repositories"
+    )
+
+
+def test_app_organization_still_lists_org_repositories(create_args, mock_retrieve_data):
+    args = create_args(as_app=True, include_repository=True, organization=True)
+    mock_retrieve_data.return_value = [{"name": "a"}]
+
+    repos = github_backup.retrieve_repositories(args, NO_USER)
+
+    assert mock_retrieve_data.call_args.args[1] == (
+        "https://api.github.com/orgs/testuser/repos"
+    )
+    assert repos == [{"name": "a"}]
+
+
+def test_app_single_repository_is_fetched_directly(create_args, mock_retrieve_data):
+    args = create_args(as_app=True, repository="dotfiles")
+    mock_retrieve_data.return_value = [{"name": "dotfiles"}]
+
+    repos = github_backup.retrieve_repositories(args, NO_USER)
+
+    assert mock_retrieve_data.call_args.args[1] == (
+        "https://api.github.com/repos/testuser/dotfiles"
+    )
+    assert repos == [{"name": "dotfiles"}]