diff --git a/injector/__init__.py b/injector/__init__.py
index 731c1c1..a62afbd 100644
--- a/injector/__init__.py
+++ b/injector/__init__.py
@@ -632,8 +632,9 @@ class Binder:
 
     def get_binding(self, interface: type) -> Tuple[Binding, 'Binder']:
         is_scope = isinstance(interface, type) and issubclass(interface, Scope)
+        is_assisted_builder = _is_specialization(interface, AssistedBuilder)
         try:
-            return self._get_binding(interface, only_this_binder=is_scope)
+            return self._get_binding(interface, only_this_binder=is_scope or is_assisted_builder)
         except (KeyError, UnsatisfiedRequirement):
             if is_scope:
                 scope = interface
diff --git a/injector_test.py b/injector_test.py
index 76e9bd2..80cca82 100644
--- a/injector_test.py
+++ b/injector_test.py
@@ -805,6 +805,19 @@ def test_assisted_builder_injection_is_safe_to_use_with_multiple_injectors():
     assert (b1._injector, b2._injector) == (i1, i2)
 
 
+def test_assisted_builder_injection_is_safe_to_use_with_child_injectors():
+    class X:
+        @inject
+        def __init__(self, builder: AssistedBuilder[NeedsAssistance]):
+            self.builder = builder
+
+    i1 = Injector()
+    i2 = i1.create_child_injector()
+    b1 = i1.get(X).builder
+    b2 = i2.get(X).builder
+    assert (b1._injector, b2._injector) == (i1, i2)
+
+
 class TestThreadSafety:
     def setup(self):
         self.event = threading.Event()