diff --git a/aiida/orm/entities.py b/aiida/orm/entities.py
index f44cef976d..68d80efa0b 100644
--- a/aiida/orm/entities.py
+++ b/aiida/orm/entities.py
@@ -15,6 +15,7 @@
 
 from plumpy.base.utils import call_with_super_check, super_check
 
+from aiida.common.exceptions import InvalidOperation
 from aiida.common.lang import classproperty, type_check
 from aiida.common.warnings import warn_deprecation
 from aiida.manage import get_manager
@@ -217,6 +218,10 @@ def __init__(self, backend_entity: BackendEntityType) -> None:
         self._backend_entity = backend_entity
         call_with_super_check(self.initialize)
 
+    def __getstate__(self):
+        """Prevent an ORM entity instance from being pickled."""
+        raise InvalidOperation('pickling of AiiDA ORM instances is not supported.')
+
     @super_check
     def initialize(self) -> None:
         """Initialize instance attributes.
diff --git a/tests/orm/test_entities.py b/tests/orm/test_entities.py
index 8a4ba067fc..bb290fc4da 100644
--- a/tests/orm/test_entities.py
+++ b/tests/orm/test_entities.py
@@ -9,9 +9,12 @@
 ###########################################################################
 # pylint: disable=no-self-use
 """Test for general backend entities"""
+import pickle
+
 import pytest
 
 from aiida import orm
+from aiida.common.exceptions import InvalidOperation
 
 
 @pytest.mark.usefixtures('aiida_profile_clean')
@@ -37,3 +40,8 @@ def test_collections_count(self):
             number_of_users, \
             '{} User(s) was/were found using Collections\' count() method, ' \
             'but {} User(s) was/were found using QueryBuilder directly'.format(user_collection_count, number_of_users)
+
+    def test_pickle(self):
+        """Pickling is not supported and should raise."""
+        with pytest.raises(InvalidOperation):
+            pickle.dumps(orm.Entity({}))