diff --git a/.github/workflows/prettier.yaml b/.github/workflows/prettier.yaml
new file mode 100644
index 000000000..faf73053c
--- /dev/null
+++ b/.github/workflows/prettier.yaml
@@ -0,0 +1,12 @@
+name: Prettier formatting
+on: [push, pull_request]
+
+jobs:
+  build:
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: '16.x'
+      - run: npm ci
+      - run: npm run format:check
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 000000000..7cbc61404
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,10 @@
+*.swp
+*~
+.*.haste_cache.*
+.DS_Store
+npm-debug.log
+/build
+/out
+/gh-pages
+/node_modules
+/package.json
diff --git a/package-lock.json b/package-lock.json
index f23c385d1..12d8d8560 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,7 @@
       "devDependencies": {
         "cspell": "5.3.12",
         "nodemon": "2.0.7",
+        "prettier": "^2.3.0",
         "spec-md": "3.0.2"
       }
     },
@@ -638,7 +639,6 @@
       "dependencies": {
         "anymatch": "~3.1.1",
         "braces": "~3.0.2",
-        "fsevents": "~2.3.1",
         "glob-parent": "~5.1.0",
         "is-binary-path": "~2.1.0",
         "is-glob": "~4.0.1",
@@ -1468,7 +1468,6 @@
       "integrity": "sha512-5dgndWOriYSm5cnYaJNhalLNDKOqFwyDB/rr1E9ZsGciGvKPs8R2xYGCacuf3z6K1YKDz182fd+fY3cn3pMqXQ==",
       "dev": true,
       "dependencies": {
-        "graceful-fs": "^4.1.6",
         "universalify": "^2.0.0"
       },
       "optionalDependencies": {
@@ -1754,14 +1753,23 @@
         "node": ">=4"
       }
     },
+    "node_modules/prettier": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.3.0.tgz",
+      "integrity": "sha512-kXtO4s0Lz/DW/IJ9QdWhAf7/NmPWQXkFr/r/WkR3vyI+0v8amTDxiaQSLzs8NBlytfLWX/7uQUMIW677yLKl4w==",
+      "dev": true,
+      "bin": {
+        "prettier": "bin-prettier.js"
+      },
+      "engines": {
+        "node": ">=10.13.0"
+      }
+    },
     "node_modules/prismjs": {
       "version": "1.23.0",
       "resolved": "https://registry.npmjs.org/prismjs/-/prismjs-1.23.0.tgz",
       "integrity": "sha512-c29LVsqOaLbBHuIbsTxaKENh1N2EQBOHaWv7gkHN4dgRbxSREqDnDbtFJYdpPauS4YCplMSNCABQ6Eeor69bAA==",
       "dev": true,
-      "dependencies": {
-        "clipboard": "^2.0.0"
-      },
       "optionalDependencies": {
         "clipboard": "^2.0.0"
       }
@@ -3621,6 +3629,12 @@
       "integrity": "sha1-6SQ0v6XqjBn0HN/UAddBo8gZ2Jc=",
       "dev": true
     },
+    "prettier": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.3.0.tgz",
+      "integrity": "sha512-kXtO4s0Lz/DW/IJ9QdWhAf7/NmPWQXkFr/r/WkR3vyI+0v8amTDxiaQSLzs8NBlytfLWX/7uQUMIW677yLKl4w==",
+      "dev": true
+    },
     "prismjs": {
       "version": "1.23.0",
       "resolved": "https://registry.npmjs.org/prismjs/-/prismjs-1.23.0.tgz",
diff --git a/package.json b/package.json
index 93f5ba6ba..3ef6df33f 100644
--- a/package.json
+++ b/package.json
@@ -16,12 +16,19 @@
     "test": "npm run test:build && npm run test:spellcheck",
     "test:build": "spec-md spec/GraphQL.md > /dev/null",
     "test:spellcheck": "cspell 'spec/**/*.md' README.md",
+    "format": "prettier --write '**/*.{md,yml,yaml,json}'",
+    "format:check": "prettier --check '**/*.{md,yml,yaml,json}'",
     "build": "mkdir -p out; spec-md --githubSource 'https://github.com/graphql/graphql-spec/blame/main/' spec/GraphQL.md > out/index.html",
     "watch": "nodemon -e json,md --exec 'npm run build'"
   },
   "devDependencies": {
     "cspell": "5.3.12",
     "nodemon": "2.0.7",
+    "prettier": "^2.3.0",
     "spec-md": "3.0.2"
+  },
+  "prettier": {
+    "proseWrap": "always",
+    "trailingComma": "none"
   }
 }