diff --git a/django/utils/http.py b/django/utils/http.py
index c13f44602bd..4fbb786d891 100644
--- a/django/utils/http.py
+++ b/django/utils/http.py
@@ -88,11 +88,24 @@ def urlencode(query, doseq=False):
         query = query.lists()
     elif hasattr(query, 'items'):
         query = query.items()
-    return original_urlencode(
-        [(k, [str(i) for i in v] if isinstance(v, (list, tuple)) else str(v))
-         for k, v in query],
-        doseq
-    )
+    query_params = []
+    for key, value in query:
+        if isinstance(value, (str, bytes)):
+            query_val = value
+        else:
+            try:
+                iter(value)
+            except TypeError:
+                query_val = value
+            else:
+                # Consume generators and iterators, even when doseq=True, to
+                # work around https://bugs.python.org/issue31706.
+                query_val = [
+                    item if isinstance(item, bytes) else str(item)
+                    for item in value
+                ]
+        query_params.append((key, query_val))
+    return original_urlencode(query_params, doseq)
 
 
 def cookie_date(epoch_seconds=None):
diff --git a/tests/utils_tests/test_http.py b/tests/utils_tests/test_http.py
index a7a670c85bb..41bda819679 100644
--- a/tests/utils_tests/test_http.py
+++ b/tests/utils_tests/test_http.py
@@ -47,6 +47,23 @@ class URLEncodeTests(unittest.TestCase):
             'position=Developer&name=Adrian&name=Simon',
         ])
 
+    def test_dict_with_bytes_values(self):
+        self.assertEqual(urlencode({'a': b'abc'}, doseq=True), 'a=abc')
+
+    def test_dict_with_sequence_of_bytes(self):
+        self.assertEqual(urlencode({'a': [b'spam', b'eggs', b'bacon']}, doseq=True), 'a=spam&a=eggs&a=bacon')
+
+    def test_dict_with_bytearray(self):
+        self.assertEqual(urlencode({'a': bytearray(range(2))}, doseq=True), 'a=0&a=1')
+        self.assertEqual(urlencode({'a': bytearray(range(2))}, doseq=False), 'a=%5B%270%27%2C+%271%27%5D')
+
+    def test_generator(self):
+        def gen():
+            yield from range(2)
+
+        self.assertEqual(urlencode({'a': gen()}, doseq=True), 'a=0&a=1')
+        self.assertEqual(urlencode({'a': gen()}, doseq=False), 'a=%5B%270%27%2C+%271%27%5D')
+
 
 class Base36IntTests(SimpleTestCase):
     def test_roundtrip(self):