diff --git a/tox.ini b/tox.ini
index 850068d1b..0e8ddcbd3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -74,6 +74,7 @@ commands =
     twine check dist/*
 
 [pinned]
+basepython = python3.8
 deps =
     cryptography==36.0.0
     cssselect==0.9.1
@@ -100,7 +101,7 @@ commands =
     pytest --cov=scrapy --cov-report=xml --cov-report= {posargs:--durations=10 scrapy tests}
 
 [testenv:pinned]
-basepython = python3.8
+basepython = {[pinned]basepython}
 deps =
     {[pinned]deps}
     PyDispatcher==2.0.5
@@ -110,7 +111,7 @@ setenv =
 commands = {[pinned]commands}
 
 [testenv:windows-pinned]
-basepython = python3
+basepython = {[pinned]basepython}
 deps =
     {[pinned]deps}
     PyDispatcher==2.0.5
@@ -133,7 +134,7 @@ deps =
     Twisted[http2]
 
 [testenv:extra-deps-pinned]
-basepython = python3.8
+basepython = {[pinned]basepython}
 deps =
     {[pinned]deps}
     boto3==1.20.0
@@ -150,6 +151,7 @@ commands =
     {[testenv]commands} --reactor=asyncio
 
 [testenv:asyncio-pinned]
+basepython = {[pinned]basepython}
 deps = {[testenv:pinned]deps}
 commands = {[pinned]commands} --reactor=asyncio
 install_command = {[pinned]install_command}
@@ -162,7 +164,7 @@ commands =
     pytest {posargs:--durations=10 docs scrapy tests}
 
 [testenv:pypy3-pinned]
-basepython = {[testenv:pypy3]basepython}
+basepython = pypy3.8
 deps =
     {[pinned]deps}
     PyPyDispatcher==2.1.0
@@ -215,7 +217,7 @@ commands =
     pytest --cov=scrapy --cov-report=xml --cov-report= {posargs:tests -k s3}
 
 [testenv:botocore-pinned]
-basepython = python3.8
+basepython = {[pinned]basepython}
 deps =
     {[pinned]deps}
     botocore==1.4.87