diff --git a/packages/platform-server/src/http.ts b/packages/platform-server/src/http.ts
index 981490dc47..a00ce87140 100644
--- a/packages/platform-server/src/http.ts
+++ b/packages/platform-server/src/http.ts
@@ -10,11 +10,14 @@
 const xhr2: any = require('xhr2');
 
 import {Injectable, Injector, Provider} from '@angular/core';
-
+import {DOCUMENT} from '@angular/common';
 import {HttpEvent, HttpRequest, HttpHandler, HttpBackend, XhrFactory, ɵHttpInterceptingHandler as HttpInterceptingHandler} from '@angular/common/http';
-
 import {Observable, Observer, Subscription} from 'rxjs';
 
+// @see https://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01#URI-syntax
+const isAbsoluteUrl = /^[a-zA-Z\-\+.]+:\/\//;
+const FORWARD_SLASH = '/';
+
 @Injectable()
 export class ServerXhr implements XhrFactory {
   build(): XMLHttpRequest {
@@ -102,11 +105,21 @@ export abstract class ZoneMacroTaskWrapper<S, R> {
 
 export class ZoneClientBackend extends
     ZoneMacroTaskWrapper<HttpRequest<any>, HttpEvent<any>> implements HttpBackend {
-  constructor(private backend: HttpBackend) {
+  constructor(private backend: HttpBackend, private doc: Document) {
     super();
   }
 
   handle(request: HttpRequest<any>): Observable<HttpEvent<any>> {
+    const href = this.doc.location.href;
+    if (!isAbsoluteUrl.test(request.url) && href) {
+      const urlParts = Array.from(request.url);
+      if (request.url[0] === FORWARD_SLASH && href[href.length - 1] === FORWARD_SLASH) {
+        urlParts.shift();
+      } else if (request.url[0] !== FORWARD_SLASH && href[href.length - 1] !== FORWARD_SLASH) {
+        urlParts.splice(0, 0, FORWARD_SLASH);
+      }
+      return this.wrap(request.clone({url: href + urlParts.join('')}));
+    }
     return this.wrap(request);
   }
 
@@ -115,12 +128,16 @@ export class ZoneClientBackend extends
   }
 }
 
-export function zoneWrappedInterceptingHandler(backend: HttpBackend, injector: Injector) {
+export function zoneWrappedInterceptingHandler(
+    backend: HttpBackend, injector: Injector, doc: Document) {
   const realBackend: HttpBackend = new HttpInterceptingHandler(backend, injector);
-  return new ZoneClientBackend(realBackend);
+  return new ZoneClientBackend(realBackend, doc);
 }
 
 export const SERVER_HTTP_PROVIDERS: Provider[] = [
-  {provide: XhrFactory, useClass: ServerXhr},
-  {provide: HttpHandler, useFactory: zoneWrappedInterceptingHandler, deps: [HttpBackend, Injector]}
+  {provide: XhrFactory, useClass: ServerXhr}, {
+    provide: HttpHandler,
+    useFactory: zoneWrappedInterceptingHandler,
+    deps: [HttpBackend, Injector, DOCUMENT]
+  }
 ];
diff --git a/packages/platform-server/test/integration_spec.ts b/packages/platform-server/test/integration_spec.ts
index d073987aff..c8fbdc7a19 100644
--- a/packages/platform-server/test/integration_spec.ts
+++ b/packages/platform-server/test/integration_spec.ts
@@ -793,6 +793,54 @@ describe('platform-server integration', () => {
          });
        }));
 
+    it('can make relative HttpClient requests', async () => {
+      const platform = platformDynamicServer([
+        {provide: INITIAL_CONFIG, useValue: {document: '<app></app>', url: 'http://localhost'}}
+      ]);
+      const ref = await platform.bootstrapModule(HttpClientExampleModule);
+      const mock = ref.injector.get(HttpTestingController) as HttpTestingController;
+      const http = ref.injector.get(HttpClient);
+      ref.injector.get(NgZone).run(() => {
+        http.get<string>('/testing').subscribe((body: string) => {
+          NgZone.assertInAngularZone();
+          expect(body).toEqual('success!');
+        });
+        mock.expectOne('http://localhost/testing').flush('success!');
+      });
+    });
+
+    it('can make relative HttpClient requests two slashes', async () => {
+      const platform = platformDynamicServer([
+        {provide: INITIAL_CONFIG, useValue: {document: '<app></app>', url: 'http://localhost/'}}
+      ]);
+      const ref = await platform.bootstrapModule(HttpClientExampleModule);
+      const mock = ref.injector.get(HttpTestingController) as HttpTestingController;
+      const http = ref.injector.get(HttpClient);
+      ref.injector.get(NgZone).run(() => {
+        http.get<string>('/testing').subscribe((body: string) => {
+          NgZone.assertInAngularZone();
+          expect(body).toEqual('success!');
+        });
+        mock.expectOne('http://localhost/testing').flush('success!');
+      });
+    });
+
+    it('can make relative HttpClient requests no slashes', async () => {
+      const platform = platformDynamicServer([
+        {provide: INITIAL_CONFIG, useValue: {document: '<app></app>', url: 'http://localhost'}}
+      ]);
+      const ref = await platform.bootstrapModule(HttpClientExampleModule);
+      const mock = ref.injector.get(HttpTestingController) as HttpTestingController;
+      const http = ref.injector.get(HttpClient);
+      ref.injector.get(NgZone).run(() => {
+        http.get<string>('testing').subscribe((body: string) => {
+          NgZone.assertInAngularZone();
+          expect(body).toEqual('success!');
+        });
+        mock.expectOne('http://localhost/testing').flush('success!');
+      });
+    });
+
     it('requests are macrotasks', async(() => {
          const platform = platformDynamicServer(
              [{provide: INITIAL_CONFIG, useValue: {document: '<app></app>'}}]);