diff --git a/tox.ini b/tox.ini
index 33e0c931..5acc30e2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,18 +7,20 @@ passenv =
 
 [testenv]
 extras = testing
-deps =
-     --requirement dependencies/default/requirements.txt
-     --constraint dependencies/default/constraints.txt
+install_command = python -m pip install \
+    --requirement dependencies/default/requirements.txt \
+    --constraint dependencies/default/constraints.txt \
+    {opts} {packages}
 commands = make test
 allowlist_externals =
     make
 
 [testenv:pytest-min]
 extras = testing
-deps =
-     --requirement dependencies/pytest-min/requirements.txt
-     --constraint dependencies/pytest-min/constraints.txt
+install_command = python -m pip install \
+    --requirement dependencies/pytest-min/requirements.txt \
+    --constraint dependencies/pytest-min/constraints.txt \
+    {opts} {packages}
 commands = make test
 allowlist_externals =
     make