diff --git a/celery_once/backends/file.py b/celery_once/backends/file.py
index 3b9ed6a..3f96cfe 100644
--- a/celery_once/backends/file.py
+++ b/celery_once/backends/file.py
@@ -73,4 +73,11 @@ def clear_lock(self, key):
         Remove the lock file.
         """
         lock_path = self._get_lock_path(key)
-        os.remove(lock_path)
+        try:
+            os.remove(lock_path)
+        except OSError as exc:
+            if exc.errno == errno.ENOENT:
+                # Lock file already deleted
+                pass
+            else:
+                raise exc
diff --git a/tests/unit/backends/test_file.py b/tests/unit/backends/test_file.py
index 89895cd..3c1126c 100644
--- a/tests/unit/backends/test_file.py
+++ b/tests/unit/backends/test_file.py
@@ -131,3 +131,14 @@ def test_file_clear_lock(backend, mocker):
     assert remove_mock.call_count == 1
     assert remove_mock.call_args[0] == (expected_lock_path,)
     assert ret is None
+
+
+def test_file_clear_lock_already_removed(backend, mocker):
+    key = 'test.task.key'
+    mocker.patch('celery_once.backends.file.os.remove',
+                 side_effect=OSError(errno.ENOENT, 'error'))
+    expected_lock_path = os.path.join(TEST_LOCATION,
+                                      key_to_lock_name(key))
+    ret = backend.clear_lock(key)
+
+    assert ret is None