diff --git a/tools/jenkins/run_interop.sh b/tools/jenkins/run_interop.sh
index a424aea7fc4..4a7bff33891 100755
--- a/tools/jenkins/run_interop.sh
+++ b/tools/jenkins/run_interop.sh
@@ -31,6 +31,8 @@
 # This script is invoked by Jenkins and runs interop test suite.
 set -ex
 
+export LANG=en_US.UTF-8
+
 # Enter the gRPC repo root
 cd $(dirname $0)/../..