diff --git a/pyproject.toml b/pyproject.toml
index 6b7bd6e7..89383f1e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,7 +41,7 @@ langgraph = [
     "langgraph-checkpoint>=4.0.0, <5.0.0"
 ]
 test = [
-    "black[jupyter]==26.1.0",
+    "black[jupyter]==26.3.1",
     "isort==8.0.0",
     "mypy==1.19.1",
     "pytest-asyncio==0.26.0",