diff --git a/tests/unit/test_temp_file_manager.py b/tests/unit/test_temp_file_manager.py
new file mode 100644
index 0000000..415197a
--- /dev/null
+++ b/tests/unit/test_temp_file_manager.py
@@ -0,0 +1,140 @@
+"""Unit tests for TempFileManager lifecycle and cleanup behavior."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from src.lib.exceptions import TempFileError
+from src.services.temp_file_manager import TempFileManager
+
+
+@pytest.fixture()
+def manager(tmp_path: Path) -> TempFileManager:
+    return TempFileManager(temp_dir=str(tmp_path / "temp"))
+
+
+def test_init_creates_temp_directory(tmp_path: Path) -> None:
+    temp_dir = tmp_path / "new-temp"
+    assert not temp_dir.exists()
+
+    mgr = TempFileManager(temp_dir=str(temp_dir))
+
+    assert mgr.get_temp_dir() == temp_dir
+    assert temp_dir.exists()
+
+
+def test_create_temp_file_strips_dot_extension(manager: TempFileManager) -> None:
+    path = manager.create_temp_file(".png")
+
+    assert path.exists()
+    assert path.suffix == ".png"
+    assert path in manager.get_created_files()
+
+
+def test_cleanup_temp_file_removes_file_and_tracking(manager: TempFileManager) -> None:
+    path = manager.create_temp_file("jpg")
+    assert path in manager.get_created_files()
+
+    manager.cleanup_temp_file(path)
+
+    assert not path.exists()
+    assert path not in manager.get_created_files()
+
+
+def test_cleanup_temp_file_when_cleanup_disabled(tmp_path: Path) -> None:
+    mgr = TempFileManager(temp_dir=str(tmp_path / "temp"), cleanup_enabled=False)
+    path = mgr.create_temp_file("png")
+
+    mgr.cleanup_temp_file(path)
+
+    assert path.exists()
+    assert path in mgr.get_created_files()
+
+
+def test_cleanup_temp_file_missing_file_is_noop(manager: TempFileManager) -> None:
+    missing = manager.get_temp_dir() / "missing.png"
+    manager.cleanup_temp_file(missing)
+
+
+def test_cleanup_temp_file_raises_when_unlink_fails(
+    manager: TempFileManager,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    path = manager.create_temp_file("png")
+
+    def _unlink_fail(_self: Path, _missing_ok: bool = False):
+        raise PermissionError("blocked")
+
+    monkeypatch.setattr(Path, "unlink", _unlink_fail)
+
+    with pytest.raises(TempFileError, match="Failed to cleanup temp file"):
+        manager.cleanup_temp_file(path)
+
+
+def test_cleanup_all_temp_files_removes_tracked_and_orphaned_files(manager: TempFileManager) -> None:
+    tracked = manager.create_temp_file("png")
+    orphaned = manager.get_temp_dir() / "screenshot_orphaned.png"
+    orphaned.write_bytes(b"x")
+
+    manager.cleanup_all_temp_files()
+
+    assert not tracked.exists()
+    assert not orphaned.exists()
+    assert manager.get_created_files() == []
+
+
+def test_cleanup_all_temp_files_when_disabled_keeps_files(tmp_path: Path) -> None:
+    mgr = TempFileManager(temp_dir=str(tmp_path / "temp"), cleanup_enabled=False)
+    path = mgr.create_temp_file("png")
+
+    mgr.cleanup_all_temp_files()
+
+    assert path.exists()
+
+
+def test_cleanup_all_temp_files_aggregates_errors(
+    manager: TempFileManager,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    manager.create_temp_file("png")
+
+    class _UnlinkController:
+        def __init__(self):
+            self.calls = 0
+
+        def __call__(self, _self: Path, _missing_ok: bool = False):
+            self.calls += 1
+            if self.calls == 1:
+                raise PermissionError("blocked")
+
+    controller = _UnlinkController()
+    monkeypatch.setattr(Path, "unlink", controller)
+
+    with pytest.raises(TempFileError, match="Cleanup completed with"):
+        manager.cleanup_all_temp_files()
+
+
+def test_create_temp_file_raises_temp_file_error_on_failure(
+    manager: TempFileManager,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr("src.services.temp_file_manager.tempfile.mkstemp", lambda **_kwargs: (_ for _ in ()).throw(OSError("disk full")))
+
+    with pytest.raises(TempFileError, match="Failed to create temp file"):
+        manager.create_temp_file("png")
+
+
+def test_destructor_cleanup_calls_cleanup_all(manager: TempFileManager, monkeypatch: pytest.MonkeyPatch) -> None:
+    manager.create_temp_file("png")
+    called = {"value": False}
+
+    def _cleanup():
+        called["value"] = True
+
+    monkeypatch.setattr(manager, "cleanup_all_temp_files", _cleanup)
+
+    manager.__del__()
+
+    assert called["value"] is True