diff --git a/.stylelintrc b/.stylelintrc
new file mode 100644
index 0000000000..1d86a41f98
--- /dev/null
+++ b/.stylelintrc
@@ -0,0 +1,3 @@
+{
+	"extends": "stylelint-config-ckeditor5"
+}
diff --git a/package.json b/package.json
index efee73799e..a6b12e2f4f 100644
--- a/package.json
+++ b/package.json
@@ -50,6 +50,7 @@
     "eslint-config-ckeditor5": "^2.0.0",
     "husky": "^1.3.1",
     "lint-staged": "^7.0.0",
+    "stylelint": "^11.1.1",
     "postcss-loader": "^3.0.0",
     "raw-loader": "^3.1.0",
     "style-loader": "^1.0.0",
@@ -72,11 +73,15 @@
   "scripts": {
     "build": "webpack --mode production",
     "lint": "eslint --quiet '**/*.js'",
+    "stylelint": "stylelint --quiet --allow-empty-input 'theme/**/*.css' 'docs/**/*.css'",
     "preversion": "npm run build; if [ -n \"$(git status src/ckeditor.js build/ --porcelain)\" ]; then git add -u src/ckeditor.js build/ && git commit -m 'Internal: Build.'; fi"
   },
   "lint-staged": {
     "**/*.js": [
       "eslint --quiet"
+    ],
+    "**/*.css": [
+      "stylelint --quiet --allow-empty-input"
     ]
   },
   "eslintIgnore": [