diff --git a/tox.ini b/tox.ini
index 615164714..8e38112e5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -19,6 +19,7 @@ deps =
     sybil >= 1.3.0  # https://github.com/cjw296/sybil/issues/20#issuecomment-605433422
     testfixtures
     pywin32; sys_platform == "win32"
+    cffi >= 1.17.0rc1; python_version >= '3.13'
 
 [testenv]
 deps =