diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7d2c1861..efb78236 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 - Implement an in-memory cache store to save parsed and validated documents and provide performance benefits for successful executions of the same document. [PR #2111](https://github.com/apollographql/apollo-server/pull/2111) (`2.4.0-alpha.0`)
 - New `apollo-server-fastify` integration ([@rkorrelboom](https://github.com/rkorrelboom) in [#1971](https://github.com/apollostack/apollo-server/pull/1971))
 
+- Fix: Serialize arrays as JSON on fetch in `RESTDataSource`. [PR #2219](https://github.com/apollographql/apollo-server/pull/2219)
+
 ### v2.3.3
 
 - `apollo-server` (only): Stop double-invocation of `serverWillStart` life-cycle event.  (More specific integrations - e.g. Express, Koa, Hapi, etc. - were unaffected.) [PR #2239](https://github.com/apollographql/apollo-server/pull/2239)
diff --git a/package-lock.json b/package-lock.json
index f5d29d91..6791d318 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1347,9 +1347,9 @@
       }
     },
     "@types/jest": {
-      "version": "23.3.13",
-      "resolved": "https://registry.npmjs.org/@types/jest/-/jest-23.3.13.tgz",
-      "integrity": "sha512-ePl4l+7dLLmCucIwgQHAgjiepY++qcI6nb8eAwGNkB6OxmTe3Z9rQU3rSpomqu42PCCnlThZbOoxsf+qylJsLA==",
+      "version": "23.3.14",
+      "resolved": "https://registry.npmjs.org/@types/jest/-/jest-23.3.14.tgz",
+      "integrity": "sha512-Q5hTcfdudEL2yOmluA1zaSyPbzWPmJ3XfSWeP3RyoYvS9hnje1ZyagrZOuQ6+1nQC1Gw+7gap3pLNL3xL6UBug==",
       "dev": true
     },
     "@types/joi": {
@@ -6733,9 +6733,9 @@
       }
     },
     "hapi": {
-      "version": "17.8.3",
-      "resolved": "https://registry.npmjs.org/hapi/-/hapi-17.8.3.tgz",
-      "integrity": "sha512-HH+w5qxtEdnYgwYdeqUbVi7VnWWHl1U2eW6tyu6P681VhJimGYgDBpbcqCjKta61yWS27E1LG8rNLj+0Renj4w==",
+      "version": "17.8.4",
+      "resolved": "https://registry.npmjs.org/hapi/-/hapi-17.8.4.tgz",
+      "integrity": "sha512-KmW0a36iXesMKKGNI4J/Ht37f2HQP6W6iKce8U5lxf+GtSH70zSh7q3D56Ro/a4Q5U5M60gSSU4esMVFxttANQ==",
       "dev": true,
       "requires": {
         "accept": "3.x.x",
@@ -6812,9 +6812,9 @@
           }
         },
         "bourne": {
-          "version": "1.0.0",
-          "resolved": "https://registry.npmjs.org/bourne/-/bourne-1.0.0.tgz",
-          "integrity": "sha512-938G7p21n3x3FiGnZcoN8Spv7EHOgFRnUStCby2/2fYnkY+fFU5TobsN4xCo5kW/jniYJP8KWjBFTzM4oq+ewg==",
+          "version": "1.1.1",
+          "resolved": "https://registry.npmjs.org/bourne/-/bourne-1.1.1.tgz",
+          "integrity": "sha512-Ou0l3W8+n1FuTOoIfIrCk9oF9WVWc+9fKoAl67XQr9Ws0z7LgILRZ7qtc9xdT4BveSKtnYXfKPgn8pFAqeQRew==",
           "dev": true
         },
         "call": {
diff --git a/package.json b/package.json
index 4e349b6b..26f0e3bd 100644
--- a/package.json
+++ b/package.json
@@ -72,7 +72,7 @@
     "@types/fibers": "0.0.30",
     "@types/graphql": "14.0.5",
     "@types/hapi": "17.8.5",
-    "@types/jest": "23.3.13",
+    "@types/jest": "23.3.14",
     "@types/koa-multer": "1.0.0",
     "@types/koa-router": "7.0.39",
     "@types/lodash": "4.14.120",
@@ -104,7 +104,7 @@
     "graphql-subscriptions": "1.0.0",
     "graphql-tag": "2.10.1",
     "graphql-tools": "4.0.4",
-    "hapi": "17.8.3",
+    "hapi": "17.8.4",
     "husky": "1.3.1",
     "jest": "23.6.0",
     "jest-junit": "5.2.0",
diff --git a/packages/apollo-datasource-rest/src/RESTDataSource.ts b/packages/apollo-datasource-rest/src/RESTDataSource.ts
index 0c8f9bf1..26d7a492 100644
--- a/packages/apollo-datasource-rest/src/RESTDataSource.ts
+++ b/packages/apollo-datasource-rest/src/RESTDataSource.ts
@@ -218,11 +218,12 @@ export abstract class RESTDataSource<TContext = any> extends DataSource {
       url.searchParams.append(name, value);
     }
 
-    // We accept arbitrary objects as body and serialize them as JSON
+    // We accept arbitrary objects and arrays as body and serialize them as JSON
     if (
       options.body !== undefined &&
       options.body !== null &&
       (options.body.constructor === Object ||
+        Array.isArray(options.body) ||
         ((options.body as any).toJSON &&
           typeof (options.body as any).toJSON === 'function'))
     ) {
diff --git a/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts b/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts
index 48868de3..477ad4cc 100644
--- a/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts
+++ b/packages/apollo-datasource-rest/src/__tests__/RESTDataSource.test.ts
@@ -268,6 +268,31 @@ describe('RESTDataSource', () => {
       );
     });
 
+    it('serializes a request body that is an array as JSON', async () => {
+      const dataSource = new class extends RESTDataSource {
+        baseURL = 'https://api.example.com';
+
+        postFoo(foo) {
+          return this.post('foo', foo);
+        }
+      }();
+
+      dataSource.httpCache = httpCache;
+
+      fetch.mockJSONResponseOnce();
+
+      await dataSource.postFoo(['foo', 'bar']);
+
+      expect(fetch.mock.calls.length).toEqual(1);
+      expect(fetch.mock.calls[0][0].url).toEqual('https://api.example.com/foo');
+      expect(fetch.mock.calls[0][0].body).toEqual(
+        JSON.stringify(['foo', 'bar']),
+      );
+      expect(fetch.mock.calls[0][0].headers.get('Content-Type')).toEqual(
+        'application/json',
+      );
+    });
+
     it('serializes a request body that has a toJSON method as JSON', async () => {
       const dataSource = new class extends RESTDataSource {
         baseURL = 'https://api.example.com';