diff --git a/constraints.txt b/constraints.txt
new file mode 100644
index 0000000..579c9ad
--- /dev/null
+++ b/constraints.txt
@@ -0,0 +1 @@
+black<24
diff --git a/tox.ini b/tox.ini
index d87fa4b..f8bfc77 100644
--- a/tox.ini
+++ b/tox.ini
@@ -30,6 +30,7 @@
 
 [testenv]
 deps =
+    -c constraints.txt
     black
     flake8
     isort
@@ -44,6 +45,7 @@
 [testenv:lint]
 skip_install = true
 deps =
+    -c constraints.txt
     black
     flake8
 commands =
@@ -53,6 +55,7 @@
 [testenv:format]
 skip_install = true
 deps =
+    -c constraints.txt
     black
     flake8
 commands =