diff --git a/docs/misc/changelog.rst b/docs/misc/changelog.rst
index fcbfb66..e17c3df 100644
--- a/docs/misc/changelog.rst
+++ b/docs/misc/changelog.rst
@@ -4,6 +4,32 @@ Changelog
 ==========
 
 
+Release 1.5.1a0 (WIP)
+---------------------------
+
+Breaking Changes:
+^^^^^^^^^^^^^^^^^
+
+New Features:
+^^^^^^^^^^^^^
+
+SB3-Contrib
+^^^^^^^^^^^
+
+Bug Fixes:
+^^^^^^^^^^
+- Fixed saving and loading large policies greater than 2GB (@jkterry1, @ycheng517)
+
+Deprecations:
+^^^^^^^^^^^^^
+
+Others:
+^^^^^^^
+
+Documentation:
+^^^^^^^^^^^^^^
+
+
 Release 1.5.0 (2022-03-25)
 ---------------------------
 
@@ -931,4 +957,4 @@ And all the contributors:
 @wkirgsn @AechPro @CUN-bjy @batu @IljaAvadiev @timokau @kachayev @cleversonahum
 @eleurent @ac-93 @cove9988 @theDebugger811 @hsuehch @Demetrio92 @thomasgubler @IperGiove @ScheiklP
 @simoninithomas @armandpl @manuel-delverme @Gautam-J @gianlucadecola @buoyancy99 @caburu @xy9485
-@Gregwar
+@Gregwar @ycheng517
diff --git a/scripts/run_tests.sh b/scripts/run_tests.sh
index a379507..9ecb207 100755
--- a/scripts/run_tests.sh
+++ b/scripts/run_tests.sh
@@ -1,2 +1,2 @@
 #!/bin/bash
-python3 -m pytest --cov-config .coveragerc --cov-report html --cov-report term --cov=. -v --color=yes
+python3 -m pytest --cov-config .coveragerc --cov-report html --cov-report term --cov=. -v --color=yes -m "not expensive"
diff --git a/setup.cfg b/setup.cfg
index e23ad45..5bc66c2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -15,6 +15,8 @@ filterwarnings =
 		ignore::UserWarning:gym
 		ignore:SelectableGroups dict interface is deprecated.:DeprecationWarning
 		ignore:`np.bool` is a deprecated alias for the builtin `bool`:DeprecationWarning
+markers =
+    expensive: marks tests as expensive (deselect with '-m "not expensive"')
 
 [pytype]
 inputs = stable_baselines3
diff --git a/stable_baselines3/common/save_util.py b/stable_baselines3/common/save_util.py
index dcacfba..e0b104f 100644
--- a/stable_baselines3/common/save_util.py
+++ b/stable_baselines3/common/save_util.py
@@ -314,11 +314,11 @@ def save_to_zip_file(
         if data is not None:
             archive.writestr("data", serialized_data)
         if pytorch_variables is not None:
-            with archive.open("pytorch_variables.pth", mode="w") as pytorch_variables_file:
+            with archive.open("pytorch_variables.pth", mode="w", force_zip64=True) as pytorch_variables_file:
                 th.save(pytorch_variables, pytorch_variables_file)
         if params is not None:
             for file_name, dict_ in params.items():
-                with archive.open(file_name + ".pth", mode="w") as param_file:
+                with archive.open(file_name + ".pth", mode="w", force_zip64=True) as param_file:
                     th.save(dict_, param_file)
         # Save metadata: library version when file was saved
         archive.writestr("_stable_baselines3_version", sb3.__version__)
diff --git a/stable_baselines3/version.txt b/stable_baselines3/version.txt
index bc80560..33271c4 100644
--- a/stable_baselines3/version.txt
+++ b/stable_baselines3/version.txt
@@ -1 +1 @@
-1.5.0
+1.5.1a0
diff --git a/tests/test_save_load.py b/tests/test_save_load.py
index 19b2c90..452e6fb 100644
--- a/tests/test_save_load.py
+++ b/tests/test_save_load.py
@@ -656,3 +656,24 @@ def test_open_file(tmp_path):
     with pytest.raises(ValueError):
         buff.close()
         open_path(buff, "w")
+
+
+@pytest.mark.expensive
+def test_save_load_large_model(tmp_path):
+    """
+    Test saving and loading a model with a large policy that is greater than 2GB. We
+    test only one algorithm since all algorithms share the same code for loading and
+    saving the model.
+    """
+    env = select_env(TD3)
+    kwargs = dict(policy_kwargs=dict(net_arch=[8192, 8192, 8192]), device="cpu")
+    model = TD3("MlpPolicy", env, **kwargs)
+
+    # test saving
+    model.save(tmp_path / "test_save")
+
+    # test loading
+    model = TD3.load(str(tmp_path / "test_save.zip"), env=env, **kwargs)
+
+    # clear file from os
+    os.remove(tmp_path / "test_save.zip")