diff --git a/pyproject.toml b/pyproject.toml
index 0fbdb9c9..25ebc56b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -54,7 +54,7 @@ alembic = "alembic.config:main"
 tests = [
     "pytest>8,<10",
     "pytest-xdist",
-    "black==25.9.0",  # for test_post_write.py
+    "black==26.5.1",  # for test_post_write.py
     "zimports",  # for stub testing
     "tzdata",
     "junitparser"
@@ -78,7 +78,7 @@ lint = [
     "flake8-rst-docstrings",
     "pydocstyle",
     "pygments",
-    "black==25.9.0"
+    "black==26.5.1"
 ]
 
 mypy = [