diff --git a/.gitmodules b/.gitmodules
index 62e557c1..3430dba8 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -16,3 +16,6 @@
 [submodule "third_party/fasm"]
 	path = third_party/fasm
 	url = https://github.com/SymbiFlow/fasm.git
+[submodule "third_party/python-sdf-timing"]
+	path = third_party/python-sdf-timing
+	url = https://github.com/SymbiFlow/python-sdf-timing.git
diff --git a/third_party/python-sdf-timing b/third_party/python-sdf-timing
new file mode 160000
index 00000000..309e9ca2
--- /dev/null
+++ b/third_party/python-sdf-timing
@@ -0,0 +1 @@
+Subproject commit 309e9ca2208b659fc553def93704a6848e227901