diff --git a/src/core/config.js b/src/core/config.js
index ca3b7736315..474491331e7 100644
--- a/src/core/config.js
+++ b/src/core/config.js
@@ -18,6 +18,7 @@ export type Config = {
   keyCodes: { [key: string]: number | Array<number> };
   // platform
   isReservedTag: (x?: string) => boolean;
+  isReservedAttr: (x?: string) => boolean;
   parsePlatformTagName: (x: string) => string;
   isUnknownElement: (x?: string) => boolean;
   getTagNamespace: (x?: string) => string | void;
@@ -71,6 +72,12 @@ export default ({
    */
   isReservedTag: no,
 
+  /**
+   * Check if an attribute is reserved so that it cannot be used as a component
+   * prop. This is platform-dependent and may be overwritten.
+   */
+  isReservedAttr: no,
+
   /**
    * Check if a tag is an unknown element.
    * Platform-dependent.
diff --git a/src/core/instance/state.js b/src/core/instance/state.js
index a6036018d78..d2d8fa14998 100644
--- a/src/core/instance/state.js
+++ b/src/core/instance/state.js
@@ -1,5 +1,6 @@
 /* @flow */
 
+import config from '../config'
 import Dep from '../observer/dep'
 import Watcher from '../observer/watcher'
 
@@ -53,7 +54,11 @@ export function initState (vm: Component) {
   if (opts.watch) initWatch(vm, opts.watch)
 }
 
-const isReservedProp = { key: 1, ref: 1, slot: 1 }
+const isReservedProp = {
+  key: 1,
+  ref: 1,
+  slot: 1
+}
 
 function initProps (vm: Component, propsOptions: Object) {
   const propsData = vm.$options.propsData || {}
@@ -69,7 +74,7 @@ function initProps (vm: Component, propsOptions: Object) {
     const value = validateProp(key, propsOptions, propsData, vm)
     /* istanbul ignore else */
     if (process.env.NODE_ENV !== 'production') {
-      if (isReservedProp[key]) {
+      if (isReservedProp[key] || config.isReservedAttr(key)) {
         warn(
           `"${key}" is a reserved attribute and cannot be used as component prop.`,
           vm
diff --git a/src/entries/web-runtime.js b/src/entries/web-runtime.js
index 3d0a76ef658..7e55d6ae8db 100644
--- a/src/entries/web-runtime.js
+++ b/src/entries/web-runtime.js
@@ -13,6 +13,7 @@ import {
   query,
   mustUseProp,
   isReservedTag,
+  isReservedAttr,
   getTagNamespace,
   isUnknownElement
 } from 'web/util/index'
@@ -20,6 +21,7 @@ import {
 // install platform specific utils
 Vue.config.mustUseProp = mustUseProp
 Vue.config.isReservedTag = isReservedTag
+Vue.config.isReservedAttr = isReservedAttr
 Vue.config.getTagNamespace = getTagNamespace
 Vue.config.isUnknownElement = isUnknownElement
 
diff --git a/src/platforms/web/util/attrs.js b/src/platforms/web/util/attrs.js
index c8afc748a07..1758b4708b5 100644
--- a/src/platforms/web/util/attrs.js
+++ b/src/platforms/web/util/attrs.js
@@ -2,6 +2,10 @@
 
 import { makeMap } from 'shared/util'
 
+// these are reserved for web because they are directly compiled away
+// during template compilation
+export const isReservedAttr = makeMap('style,class')
+
 // attributes that should be using props for binding
 const acceptValue = makeMap('input,textarea,option,select')
 export const mustUseProp = (tag: string, type: ?string, attr: string): boolean => {