diff --git a/src/cpl_query/_extension/__init__.py b/src/cpl_query/_extension/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/src/cpl_query/extension/iterable.py b/src/cpl_query/_extension/iterable.py
similarity index 91%
rename from src/cpl_query/extension/iterable.py
rename to src/cpl_query/_extension/iterable.py
index d5844620..690a8cd3 100644
--- a/src/cpl_query/extension/iterable.py
+++ b/src/cpl_query/_extension/iterable.py
@@ -1,7 +1,7 @@
 from typing import Optional, Callable
 
-from .ordered_iterable import OrderedIterable
-from .ordered_iterable_abc import OrderedIterableABC
+from cpl_query._extension.ordered_iterable import OrderedIterable
+from cpl_query.extension.ordered_iterable_abc import OrderedIterableABC
 from .._query.any_query import any_query
 from .._query.first_query import first_or_default_query, first_query
 from .._query.for_each_query import for_each_query
diff --git a/src/cpl_query/extension/ordered_iterable.py b/src/cpl_query/_extension/ordered_iterable.py
similarity index 100%
rename from src/cpl_query/extension/ordered_iterable.py
rename to src/cpl_query/_extension/ordered_iterable.py
diff --git a/src/cpl_query/extension/list.py b/src/cpl_query/extension/list.py
index 7496d43c..94eeeb09 100644
--- a/src/cpl_query/extension/list.py
+++ b/src/cpl_query/extension/list.py
@@ -1,4 +1,4 @@
-from cpl_query.extension.iterable import Iterable
+from .._extension.iterable import Iterable
 
 
 class List(Iterable):