diff --git a/gulp/sass.js b/gulp/sass.js
index 60166fdea..056886fe1 100755
--- a/gulp/sass.js
+++ b/gulp/sass.js
@@ -25,7 +25,7 @@ gulp.task('sass-extensions', (done) => {
 gulp.task('sass', () => {
   return gulp.src(config.paths.assets + '/sass/*.scss')
     .pipe(sourcemaps.init())
-    .pipe(sass({ outputStyle: 'expanded' }).on('error', (error) => {
+    .pipe(sass({ style: 'expanded' }).on('error', (error) => {
       // write a blank application.css to force browser refresh on error
       if (!fs.existsSync(stylesheetDirectory)) {
         fs.mkdirSync(stylesheetDirectory)
diff --git a/package.json b/package.json
index 8a033574b..6d2e4c698 100644
--- a/package.json
+++ b/package.json
@@ -35,7 +35,7 @@
     "govuk-markdown": "^0.8.0",
     "gulp": "^5.0.0",
     "gulp-nodemon": "^2.5.0",
-    "gulp-sass": "^5.0.0",
+    "gulp-sass": "^6.0.0",
     "gulp-sourcemaps": "^3.0.0",
     "inquirer": "^8.2.6",
     "js-yaml": "^4.1.0",