diff --git a/test_requirements.txt b/test_requirements.txt
index 07d2fbc..8ec95e6 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,3 +1,4 @@
+hypothesis
 pytest
 pytest-cov
-hypothesis
+pytest-run-parallel
diff --git a/tox.ini b/tox.ini
index 8e4db44..7f0811c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,8 @@ envlist = py37, py38, py39, py310, py311, py312, pypy, lint
 
 [testenv]
 deps= -r{toxinidir}/test_requirements.txt
-commands= python -bb -m pytest --cov brotlicffi {posargs} {toxinidir}/test/
+commands=
+    python -bb -m pytest --iterations=8 --parallel-threads=auto --cov brotlicffi {posargs} {toxinidir}/test/
 
 [testenv:pypy]
 # temporarily disable coverage testing on PyPy due to performance problems