diff --git a/pyproject.toml b/pyproject.toml
index ddd40a08e..87132defb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,7 +37,7 @@ crc32c = ["crc32c"]
 lz4 = ["lz4"]
 snappy = ["python-snappy"]
 zstd = ["zstandard"]
-testing = ["pytest", "mock; python_version < '3.3'", "pytest-mock"]
+testing = ["pytest", "mock; python_version < '3.3'", "pytest-mock", "pytest-timeout"]
 
 [tool.setuptools]
 include-package-data = false