diff --git a/django/contrib/postgres/fields/array.py b/django/contrib/postgres/fields/array.py
index 87760613fb..ceac798604 100644
--- a/django/contrib/postgres/fields/array.py
+++ b/django/contrib/postgres/fields/array.py
@@ -198,7 +198,11 @@ class ArrayLenTransform(Transform):
 
     def as_sql(self, compiler, connection):
         lhs, params = compiler.compile(self.lhs)
-        return 'array_length(%s, 1)' % lhs, params
+        # Distinguish NULL and empty arrays
+        return (
+            'CASE WHEN %(lhs)s IS NULL THEN NULL ELSE '
+            'coalesce(array_length(%(lhs)s, 1), 0) END'
+        ) % {'lhs': lhs}, params
 
 
 class IndexTransform(Transform):
diff --git a/docs/releases/1.8.8.txt b/docs/releases/1.8.8.txt
index 1c4b659782..1a28efe167 100644
--- a/docs/releases/1.8.8.txt
+++ b/docs/releases/1.8.8.txt
@@ -11,3 +11,6 @@ Bugfixes
 
 * Fixed incorrect ``unique_together`` field name generation by ``inspectdb``
   (:ticket:`25274`).
+
+* Corrected ``__len`` query lookup on ``ArrayField`` for empty arrays
+  (:ticket:`25772`).
diff --git a/tests/postgres_tests/test_array.py b/tests/postgres_tests/test_array.py
index fb7eb16da2..b514a4329e 100644
--- a/tests/postgres_tests/test_array.py
+++ b/tests/postgres_tests/test_array.py
@@ -218,6 +218,13 @@ class TestQuerying(TestCase):
             self.objs[0:3]
         )
 
+    def test_len_empty_array(self):
+        obj = NullableIntegerArrayModel.objects.create(field=[])
+        self.assertSequenceEqual(
+            NullableIntegerArrayModel.objects.filter(field__len=0),
+            [obj]
+        )
+
     def test_slice(self):
         self.assertSequenceEqual(
             NullableIntegerArrayModel.objects.filter(field__0_1=[2]),