diff --git a/package-build.el b/package-build.el
index 1541f549..3b094456 100644
--- a/package-build.el
+++ b/package-build.el
@@ -375,6 +375,7 @@ Return a cons cell whose `car' is the root and whose `cdr' is the repository."
         (pb/run-process nil "git" "clone" repo dir)))
       (pb/run-process dir "git" "reset" "--hard"
                       (or commit (concat "origin/" (pb/git-head-branch dir))))
+      (pb/run-process dir "git" "submodule" "update" "--init" "--recursive")
       (apply 'pb/run-process dir "git" "log" "-n1" "--pretty=format:'\%ci'"
              (pb/expand-source-file-list dir config))
       (pb/find-parse-time