diff --git a/.meta.toml b/.meta.toml
index 46cf128..220b611 100644
--- a/.meta.toml
+++ b/.meta.toml
@@ -27,6 +27,7 @@ additional-rules = [
 [tox]
 use-flake8 = true
 testenv-deps = [
+    "cffi >= 1.17.0rc1",
     "# The universal2 environment is for Python on macOS built with",
     "# universal2 mode instead of architecture-specific. These dependencies",
     "# must be installed separately, zc.buildout is incompatible with the",
diff --git a/tox.ini b/tox.ini
index c297298..18ab61b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,6 +18,7 @@ deps =
     setuptools < 69
     zc.buildout >= 3.0.1
     wheel > 0.37
+    cffi >= 1.17.0rc1
     # The universal2 environment is for Python on macOS built with
     # universal2 mode instead of architecture-specific. These dependencies
     # must be installed separately, zc.buildout is incompatible with the