diff --git a/.gitmodules b/.gitmodules
index f7047fb..50e41c1 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -2,3 +2,7 @@
 	path = lib/pybind11
 	url = https://github.com/pybind/pybind11
 	branch = stable
+[submodule "lib/geant4"]
+	path = lib/geant4
+	url = https://github.com/Geant4/geant4.git
+	shallow = true
diff --git a/lib/geant4 b/lib/geant4
new file mode 160000
index 0000000..41f2dd7
--- /dev/null
+++ b/lib/geant4
@@ -0,0 +1 @@
+Subproject commit 41f2dd79968018de4efb966f2546970b30c4af78