diff --git a/setup.py b/setup.py
index c67f724a9b2..21f0d8817a8 100644
--- a/setup.py
+++ b/setup.py
@@ -776,6 +776,8 @@ class PyBuildExt(build_ext):
                         extra_link_args=['-framework', 'Carbon']) )
                 exts.append( Extension('_Icn', ['icn/_Icnmodule.c'],
                         extra_link_args=['-framework', 'Carbon']) )
+                exts.append( Extension('_IBCarbon', ['ibcarbon/_IBCarbon.c'],
+                        extra_link_args=['-framework', 'Carbon']) )
                 exts.append( Extension('_List', ['list/_Listmodule.c'],
                         extra_link_args=['-framework', 'Carbon']) )
                 exts.append( Extension('_Menu', ['menu/_Menumodule.c'],