diff --git a/requirements-pypy.txt b/requirements-pypy.txt
deleted file mode 100644
index 8b7de010..00000000
--- a/requirements-pypy.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-fonttools[unicode,ufo]==4.22.0
-cu2qu==1.6.7
-glyphsLib==5.3.2
-ufo2ft==2.21.0
-MutatorMath==3.0.1
-fontMath==0.6.0
-defcon==0.8.1
-booleanOperations==0.9.0
-ufoLib2==0.8.0
-attrs==20.3.0
-cffsubr==0.2.8
-compreffor==0.5.1
diff --git a/requirements.txt b/requirements.txt
index d64a4b6f..fb67c31f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,10 +1,13 @@
-fonttools[unicode,ufo,lxml]==4.22.0
+fonttools[unicode,ufo,lxml]==4.22.0 ; platform_python_implementation == 'CPython'
+fonttools[unicode,ufo]==4.22.0 ; platform_python_implementation != 'CPython'
 cu2qu==1.6.7
 glyphsLib==5.3.2
-ufo2ft[pathops]==2.21.0
+ufo2ft[pathops]==2.21.0 ; platform_python_implementation == 'CPython'
+ufo2ft==2.21.0 ; platform_python_implementation != 'CPython'
 MutatorMath==3.0.1
 fontMath==0.6.0
-defcon[lxml]==0.8.1
+defcon[lxml]==0.8.1 ; platform_python_implementation == 'CPython'
+defcon==0.8.1 ; platform_python_implementation != 'CPython'
 booleanOperations==0.9.0
 ufoLib2==0.8.0
 attrs==20.3.0
diff --git a/test_requirements.txt b/test_requirements.txt
index 8dc3e09b..4f1f6e2a 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,5 +1,5 @@
 pytest>=4.5.0
 coverage>=5
-black
-isort
-flake8-bugbear
+black ; platform_python_implementation == 'CPython'
+isort ; platform_python_implementation == 'CPython'
+flake8-bugbear ; platform_python_implementation == 'CPython'
diff --git a/tox.ini b/tox.ini
index 33639c4c..1adf3788 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,16 +11,6 @@ download = true
 commands =
     coverage run --parallel-mode -m pytest {posargs}
 
-[testenv:pypy3]
-deps =
-    -r requirements-pypy.txt
-    pytest
-    coverage
-; download the latest pip, setuptools and wheel when creating the venv
-download = true
-commands =
-    coverage run --parallel-mode -m pytest {posargs}
-
 [testenv:lint]
 skip_install = true
 deps =