diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ef79e43d5..a239e7e14 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -90,3 +90,38 @@ jobs:
 
       - name: Run style checks
         run: uv run tox -e style
+
+  windows:
+    # Service containers do not run on Windows runners, so this job starts the
+    # PostgreSQL the image ships (service disabled, user postgres, password
+    # root). Unit tests only: behave drives pgcli through pexpect.spawn, which
+    # does not exist on Windows.
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: astral-sh/setup-uv@c7f87aa956e4c323abf06d5dec078e358f6b4d04 # v6.0.0
+        with:
+          version: "latest"
+
+      - name: Set up Python
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: "3.13"
+
+      - name: Start PostgreSQL
+        run: |
+          $pg = Get-Service -Name "postgresql*"
+          Set-Service -InputObject $pg -StartupType Manual
+          Start-Service -InputObject $pg
+          & "$env:PGBIN\pg_isready.exe" --timeout 30
+
+      - name: Install requirements
+        run: uv sync --all-extras -p 3.13
+
+      - name: Run unit tests
+        env:
+          PGHOST: localhost
+          PGUSER: postgres
+          PGPASSWORD: root
+        run: uv run tox -e py3.13
diff --git a/tests/test_main.py b/tests/test_main.py
index 319a7672f..baf0300a9 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -939,7 +939,8 @@ def test_edit_named_query():
     """Test \\ne edits/creates a named query via the external editor."""
     from pgspecial.namedqueries import NamedQueries
 
-    with tempfile.TemporaryDirectory() as tmpdir:
+    # pgcli keeps its log open, which Windows will not delete at cleanup.
+    with tempfile.TemporaryDirectory(ignore_cleanup_errors=True) as tmpdir:
         config_file = os.path.join(tmpdir, "config")
         with open(config_file, "w") as f:
             f.write("[main]\n")
diff --git a/tests/test_pgcompleter.py b/tests/test_pgcompleter.py
index bf38db236..f3ea46f60 100644
--- a/tests/test_pgcompleter.py
+++ b/tests/test_pgcompleter.py
@@ -1,7 +1,6 @@
 import json
 import pytest
 from pgcli import pgcompleter
-import tempfile
 from prompt_toolkit.document import Document
 
 
@@ -87,17 +86,17 @@ def test_generate_alias_can_use_alias_map(table_name, alias_map, alias):
         ("some_table", {"some_table": "my_alias"}, "my_alias"),
     ],
 )
-def test_pgcompleter_alias_uses_configured_alias_map(table_name, alias_map, alias):
-    with tempfile.NamedTemporaryFile(mode="w", suffix=".json") as alias_map_file:
-        alias_map_file.write(json.dumps(alias_map))
-        alias_map_file.seek(0)
-        completer = pgcompleter.PGCompleter(
-            settings={
-                "generate_aliases": True,
-                "alias_map_file": alias_map_file.name,
-            }
-        )
-        assert completer.alias(table_name, []) == alias
+def test_pgcompleter_alias_uses_configured_alias_map(table_name, alias_map, alias, tmp_path):
+    # A plain file: Windows cannot reopen an open NamedTemporaryFile by name.
+    alias_map_file = tmp_path / "alias_map.json"
+    alias_map_file.write_text(json.dumps(alias_map))
+    completer = pgcompleter.PGCompleter(
+        settings={
+            "generate_aliases": True,
+            "alias_map_file": str(alias_map_file),
+        }
+    )
+    assert completer.alias(table_name, []) == alias
 
 
 @pytest.mark.parametrize(
diff --git a/tox.ini b/tox.ini
index 15f952f23..39f8e35a4 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,6 +12,8 @@ passenv = PGHOST
     PGUSER
     PGPASSWORD
     PYTHONIOENCODING
+    # getpass.getuser() reads it on Windows, which has no pwd module
+    USERNAME
 setenv =
     PYTHONIOENCODING = utf-8