diff --git a/django/db/models/expressions.py b/django/db/models/expressions.py
index 6f26dff0e0..81f8f79c71 100644
--- a/django/db/models/expressions.py
+++ b/django/db/models/expressions.py
@@ -1149,7 +1149,8 @@ class Subquery(BaseExpression, Combinable):
 
     def __init__(self, queryset, output_field=None, **extra):
         # Allow the usage of both QuerySet and sql.Query objects.
-        self.query = getattr(queryset, 'query', queryset)
+        self.query = getattr(queryset, 'query', queryset).clone()
+        self.query.subquery = True
         self.extra = extra
         super().__init__(output_field)
 
diff --git a/tests/expressions/tests.py b/tests/expressions/tests.py
index 06c9ad597a..5cf9dd1ea5 100644
--- a/tests/expressions/tests.py
+++ b/tests/expressions/tests.py
@@ -537,6 +537,15 @@ class BasicExpressionsTests(TestCase):
             qs.query.annotations['small_company'],
         )
 
+    def test_subquery_sql(self):
+        employees = Employee.objects.all()
+        employees_subquery = Subquery(employees)
+        self.assertIs(employees_subquery.query.subquery, True)
+        self.assertIs(employees.query.subquery, False)
+        compiler = employees_subquery.query.get_compiler(connection=connection)
+        sql, _ = employees_subquery.as_sql(compiler, connection)
+        self.assertIn('(SELECT ', sql)
+
     def test_in_subquery(self):
         # This is a contrived test (and you really wouldn't write this query),
         # but it is a succinct way to test the __in=Subquery() construct.