diff --git a/django/db/transaction.py b/django/db/transaction.py
index 6cd078d94d..31d717f4d2 100644
--- a/django/db/transaction.py
+++ b/django/db/transaction.py
@@ -304,7 +304,11 @@ def commit_on_success(using=None):
                     raise
                 else:
                     if is_dirty(using=db):
-                        commit(using=db)
+                        try:
+                            commit(using=db)
+                        except:
+                            rollback(using=db)
+                            raise
                 return res
             finally:
                 leave_transaction_management(using=db)
diff --git a/tests/modeltests/transactions/models.py b/tests/modeltests/transactions/models.py
index 0c1cd21a04..3ae1290b4a 100644
--- a/tests/modeltests/transactions/models.py
+++ b/tests/modeltests/transactions/models.py
@@ -130,3 +130,24 @@ Traceback (most recent call last):
 TransactionManagementError: Transaction managed block ended with pending COMMIT/ROLLBACK
 
 """
+
+# Regression for #11900: If a function wrapped by commit_on_success writes a
+# transaction that can't be committed, that transaction should be rolled back.
+# The bug is only visible using the psycopg2 backend, though
+# the fix is generally a good idea.
+pgsql_backends = ('django.db.backends.postgresql_psycopg2', 'postgresql_psycopg2',)
+if building_docs or settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] in pgsql_backends:
+    __test__['API_TESTS'] += """
+>>> def execute_bad_sql():
+...     cursor = connection.cursor()
+...     cursor.execute("INSERT INTO transactions_reporter (first_name, last_name) VALUES ('Douglas', 'Adams');")
+...     transaction.set_dirty()
+...
+>>> execute_bad_sql = transaction.commit_on_success(execute_bad_sql)
+>>> execute_bad_sql()
+Traceback (most recent call last):
+    ...
+IntegrityError: null value in column "email" violates not-null constraint
+<BLANKLINE>
+
+"""