diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..10fcbb0
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "third_party/OpenXLSX"]
+	path = third_party/OpenXLSX
+	url = https://github.com/troldal/OpenXLSX.git
diff --git a/third_party/OpenXLSX b/third_party/OpenXLSX
new file mode 160000
index 0000000..5723411
--- /dev/null
+++ b/third_party/OpenXLSX
@@ -0,0 +1 @@
+Subproject commit 5723411d47643ce3b5b9994064c26ca8cd841f13