diff --git a/.gitmodules b/.gitmodules
index d68a54d38..90b109150 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,6 @@
 [submodule "mathics/packages/Combinatorica-repo"]
 	path = mathics/packages/Combinatorica-repo
 	url = https://github.com/Mathics3/Mathics3-Combinatorica.git
+[submodule "mathics/packages/Mathics3-Rubi"]
+	path = mathics/packages/Mathics3-Rubi
+	url = git@github.com:Mathics3/Mathics3-Rubi.git