diff --git a/odoo/addons/base/tests/__init__.py b/odoo/addons/base/tests/__init__.py
index 49b05903c9b..ee39940dedf 100644
--- a/odoo/addons/base/tests/__init__.py
+++ b/odoo/addons/base/tests/__init__.py
@@ -54,6 +54,7 @@ from . import test_reports
 from . import test_test_retry
 from . import test_test_suite
 from . import test_tests_tags
+from . import test_transactions
 from . import test_form_create
 from . import test_cloc
 from . import test_profiler
diff --git a/odoo/addons/base/tests/test_transactions.py b/odoo/addons/base/tests/test_transactions.py
new file mode 100644
index 00000000000..669f384a44e
--- /dev/null
+++ b/odoo/addons/base/tests/test_transactions.py
@@ -0,0 +1,41 @@
+from odoo.tests.common import TransactionCase
+
+
+class TestTransactionEnvs(TransactionCase):
+    def test_transation_envs_weakrefs(self):
+        transaction = self.env.transaction
+        starting_envs = set(transaction.envs)
+        base_x = self.env['base'].with_context(test_stuff=False)
+        self.assertIn(base_x.env, transaction.envs)
+        del base_x
+        self.assertEqual(set(transaction.envs), starting_envs)
+
+    def do_stuff_with_env(self):
+        base_test = self.env['base'].with_context(test_stuff=False)
+        base_test |= self.env['base'].with_context(test_stuff=1)
+        base_test |= self.env['base'].with_context(test_stuff=2)
+        return base_test
+
+    def test_transation_envs_weakrefs_call(self):
+        transaction = self.env.transaction
+        starting_envs = set(transaction.envs)
+        self.do_stuff_with_env()
+        self.assertEqual(set(transaction.envs), starting_envs)
+
+    def test_transation_envs_weakrefs_return(self):
+        transaction = self.env.transaction
+        starting_envs = set(transaction.envs)
+        base_test = self.do_stuff_with_env()
+        self.assertEqual(set(transaction.envs), starting_envs | {base_test.env})
+
+    def test_transation_envs_ordered(self):
+        transaction = self.env.transaction
+        starting_envs = set(transaction.envs)
+        # create environments in a certain order, not sorted on item
+        items = [3, 8, 1, 5, 2, 7, 6, 9, 0, 4]
+        envs = [self.env(context={'item': item}) for item in items]
+        # check that those environments appear in order in transaction.envs
+        env_items = [env.context['item'] for env in transaction.envs if env not in starting_envs]
+        self.assertEqual(env_items, items)
+        del envs
+        self.assertEqual(set(transaction.envs), starting_envs)
diff --git a/odoo/api.py b/odoo/api.py
index 56c48c414de..9fc9a7618d6 100644
--- a/odoo/api.py
+++ b/odoo/api.py
@@ -825,6 +825,7 @@ class Transaction:
         self.registry = registry
         # weak set of environments
         self.envs = WeakSet()
+        self.envs.data = OrderedSet()  # make the weakset OrderedWeakSet
         # cache for all records
         self.cache = Cache()
         # fields to protect {field: ids}