diff --git a/tools/internal_ci/linux/grpc_master_sanitizers.sh b/tools/internal_ci/linux/grpc_master_sanitizers.sh
index 2cd0efe1588..d22387fb203 100755
--- a/tools/internal_ci/linux/grpc_master_sanitizers.sh
+++ b/tools/internal_ci/linux/grpc_master_sanitizers.sh
@@ -37,4 +37,4 @@ git submodule update --init
 
 # download docker images from dockerhub
 export DOCKERHUB_ORGANIZATION=grpctesting
-tools/run_tests/run_tests_matrix.sh -f sanitizers linux
+tools/run_tests/run_tests_matrix.py -f sanitizers linux
diff --git a/tools/internal_ci/linux/grpc_portability.sh b/tools/internal_ci/linux/grpc_portability.sh
index c7ac3bbcbee..58d3c58e707 100755
--- a/tools/internal_ci/linux/grpc_portability.sh
+++ b/tools/internal_ci/linux/grpc_portability.sh
@@ -37,4 +37,4 @@ git submodule update --init
 
 # download docker images from dockerhub
 export DOCKERHUB_ORGANIZATION=grpctesting
-tools/run_tests/run_tests_matrix.sh -f portability linux
+tools/run_tests/run_tests_matrix.py -f portability linux
diff --git a/tools/internal_ci/linux/grpc_portability_build_only.sh b/tools/internal_ci/linux/grpc_portability_build_only.sh
index edd6f916872..80b5c4cb960 100755
--- a/tools/internal_ci/linux/grpc_portability_build_only.sh
+++ b/tools/internal_ci/linux/grpc_portability_build_only.sh
@@ -37,4 +37,4 @@ git submodule update --init
 
 # download docker images from dockerhub
 export DOCKERHUB_ORGANIZATION=grpctesting
-tools/run_tests/run_tests_matrix.sh -f portability linux --build_only
+tools/run_tests/run_tests_matrix.py -f portability linux --build_only