diff --git a/config.sh b/config.sh
index 8fefca11b..4f9b0502c 100644
--- a/config.sh
+++ b/config.sh
@@ -72,7 +72,7 @@ function pre_build {
 
 function run_tests_in_repo {
     # Run Pillow tests from within source repo
-    python selftest.py
+    python3 selftest.py
     pytest
 }
 
@@ -93,17 +93,17 @@ function run_tests {
     (cd ../Pillow && run_tests_in_repo)
     # Test against expected codecs, modules and features
     local ret=0
-    local codecs=$(python -c 'from PIL.features import *; print(" ".join(sorted(get_supported_codecs())))')
+    local codecs=$(python3 -c 'from PIL.features import *; print(" ".join(sorted(get_supported_codecs())))')
     if [ "$codecs" != "$EXP_CODECS" ]; then
         echo "Codecs should be: '$EXP_CODECS'; but are '$codecs'"
         ret=1
     fi
-    local modules=$(python -c 'from PIL.features import *; print(" ".join(sorted(get_supported_modules())))')
+    local modules=$(python3 -c 'from PIL.features import *; print(" ".join(sorted(get_supported_modules())))')
     if [ "$modules" != "$EXP_MODULES" ]; then
         echo "Modules should be: '$EXP_MODULES'; but are '$modules'"
         ret=1
     fi
-    local features=$(python -c 'from PIL.features import *; print(" ".join(sorted(get_supported_features())))')
+    local features=$(python3 -c 'from PIL.features import *; print(" ".join(sorted(get_supported_features())))')
     if [ "$features" != "$EXP_FEATURES" ]; then
         echo "Features should be: '$EXP_FEATURES'; but are '$features'"
         ret=1