diff --git a/immutabledict/__init__.py b/immutabledict/__init__.py
index 152ce4e..71f905a 100644
--- a/immutabledict/__init__.py
+++ b/immutabledict/__init__.py
@@ -11,6 +11,7 @@
     KeysView,
     Mapping,
     Optional,
+    Tuple,
     Type,
     TypeVar,
     ValuesView,
@@ -45,6 +46,11 @@ def __new__(cls, *args: Any, **kwargs: Any) -> immutabledict[_K, _V]:  # noqa: D
         setattr(inst, "_hash", None)
         return inst
 
+    def __reduce__(self) -> Tuple[Any, ...]:
+        # Do not store the cached hash value when pickling
+        # as the value might change across Python invocations.
+        return (self.__class__, (self._dict,))
+
     def __getitem__(self, key: _K) -> _V:
         return self._dict[key]