diff --git a/.gitmodules b/.gitmodules
index 1e806bf..220f560 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -52,3 +52,9 @@
 	branch = master
 	ignore = dirty
 	commit = 5f0e36eeb236a507631e9c822e43f742b7b6738a
+[submodule "third_party/ot-br-posix/repo"]
+	path = third_party/ot-br-posix/repo
+	url = https://github.com/openthread/ot-br-posix.git
+	branch = master
+	ignore = dirty
+	commit = 38e91052d1fb12a55c4e34073f9e399471650b4b