diff --git a/src/objective-c/tests/build_tests.sh b/src/objective-c/tests/build_tests.sh
index e7ad31e403159c03946258dca54749d3a642461f..8547bfd3a83dc4ef301480044846788b71508edd 100755
--- a/src/objective-c/tests/build_tests.sh
+++ b/src/objective-c/tests/build_tests.sh
@@ -33,6 +33,9 @@
 
 set -e
 
+# CocoaPods requires the terminal to be using UTF-8 encoding.
+export LANG=en_US.UTF-8
+
 cd $(dirname $0)
 
 hash pod 2>/dev/null || { echo >&2 "Cocoapods needs to be installed."; exit 1; }