diff --git a/pyproject.toml b/pyproject.toml
index 93d6417..5833cc6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,7 +31,7 @@ gh-pages = ["tinycss2"]
 [tool.poetry.group.dev.dependencies]
 mypy = "^1.8.0"
 pytest = "^8.0.0"
-pytest-cov = "^5.0.0"
+pytest-cov = "^6.0.0"
 ruff = "^0.6.0"
 types-pygments = "^2.17.0.20240106"
 types-colorama = "^0.4.15.20240205"