diff --git a/django/core/files/base.py b/django/core/files/base.py
index b1325291c62..641ff924c6b 100644
--- a/django/core/files/base.py
+++ b/django/core/files/base.py
@@ -104,7 +104,7 @@ class File(FileProxyMixin):
 
                 # If this is the end of a line, yield
                 # otherwise, wait for the next round
-                if line[-1] in ('\n', '\r'):
+                if line[-1:] in (b'\n', b'\r'):
                     yield line
                 else:
                     buffer_ = line
diff --git a/tests/files/tests.py b/tests/files/tests.py
index f562b5748d8..b9f8b5228ad 100644
--- a/tests/files/tests.py
+++ b/tests/files/tests.py
@@ -64,6 +64,14 @@ class FileTests(unittest.TestCase):
         self.assertFalse(hasattr(file, 'mode'))
         gzip.GzipFile(fileobj=file)
 
+    def test_file_iteration(self):
+        """
+        File objects should yield lines when iterated over.
+        Refs #22107.
+        """
+        file = File(BytesIO(b'one\ntwo\nthree'))
+        self.assertEqual(list(file), [b'one\n', b'two\n', b'three'])
+
 
 class NoNameFileTestCase(unittest.TestCase):
     """