diff --git a/tools/interop_matrix/client_matrix.py b/tools/interop_matrix/client_matrix.py
index 5de705a52a6..a5436f1b76e 100644
--- a/tools/interop_matrix/client_matrix.py
+++ b/tools/interop_matrix/client_matrix.py
@@ -139,7 +139,7 @@ LANG_RELEASE_MATRIX = {
             'v1.8.0': None
         },
         {
-            'v1.9.0': None
+            'v1.9.1': None
         },
     ],
     'python': [