diff --git a/tools/travis/validate-locale.sh b/tools/travis/validate-locale.sh
new file mode 100644
index 00000000000..3bc238dcd8f
--- /dev/null
+++ b/tools/travis/validate-locale.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# @file tools/travis/validate-json.sh
+#
+# Copyright (c) 2014-2021 Simon Fraser University
+# Copyright (c) 2010-2021 John Willinsky
+# Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
+#
+# Script to validate all JSON files in the repository (unless excluded).
+#
+
+set -e # Fail on first error
+
+# Collects all languages
+declare -A LANGUAGES=()
+for LANGUAGE in lib/pkp/locale/* lib/pkp/plugins/*/*/locale/* locale/* plugins/*/*/locale/*; do
+    LANGUAGES[$(basename $LANGUAGE)]=1
+done
+LANGUAGE_SET=${!LANGUAGES[*]}
+
+for LANGUAGE in $LANGUAGE_SET; do
+    # Look for syntax issues in the locale files
+    echo "Validating the syntax for the $LANGUAGE locale files..."
+    find lib/pkp/locale lib/pkp/plugins/*/*/locale locale plugins/*/*/locale -type f -path "*/$LANGUAGE/*.po" -print0 | xargs -0 -n1 msgfmt -c
+
+    # Look for duplicated locale entries
+    echo "Searching for duplicated locale keys in the language $LANGUAGE..."
+    readarray -d '' FILES < <(find lib/pkp/locale lib/pkp/plugins/*/*/locale -type f -path "*/$LANGUAGE/*.po" -print0)
+    if [ ${#FILES[@]} -gt 1 ]
+    then
+        OUTPUT=$(msgcomm --add-location --no-wrap --omit-header --more-than=1 ${FILES[@]})
+        if [ ${#OUTPUT} -gt 0 ]
+        then
+            echo -e "Found duplicated locale key:\n$OUTPUT"
+            exit 1
+        fi
+    fi
+    break
+done