diff --git a/README.md b/README.md
index 0df2453..524329b 100644
--- a/README.md
+++ b/README.md
@@ -87,6 +87,7 @@ const html = render(tree, options)
 |:--:|:--:|:-----:|:----------|
 |**[`singleTags`](#singletags)**|`{Array<String\|RegExp>}`|`[]`|Specify custom single tags (self closing)|
 |**[`closingSingleTag`](#closingSingleTag)**|`{String}`|[`>`](#default)|Specify the single tag closing format|
+|**[`quoteAllAttributes`](#quoteAllAttributes)**|`{Boolean}`|[`true`](#default)|Put double quotes around all tags, even when not necessary.|
 
 ### `singleTags`
 
@@ -166,6 +167,21 @@ const html = render(tree)
 <img></img>
 ```
 
+### `quoteAllAttributes`
+
+Specify if all attributes should be quoted.
+
+##### `true (Default)`
+
+```html
+<script src="index.js"></script>
+```
+
+##### `false`
+
+```html
+<script src=index.js></script>
+```
 
 [npm]: https://img.shields.io/npm/v/posthtml-render.svg
 [npm-url]: https://npmjs.com/package/posthtml-render
diff --git a/lib/index.js b/lib/index.js
index e31ef13..f959e17 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -22,22 +22,23 @@ var SINGLE_TAGS = [
   'extend'
 ]
 
-/**
- * Render PostHTML Tree to HTML
+var ATTRIBUTE_QUOTES_REQUIRED = /[\t\n\f\r " '`=<>]/
+
+/** Render PostHTML Tree to HTML
  *
- * @param  {Array|Object} tree PostHTML Tree
- * @param  {Object} options Options
+ * @param  {Array|Object} tree PostHTML Tree @param  {Object} options Options
  *
  * @return {String} HTML
  */
 function render (tree, options) {
-  /**
-   * Options
+  /** Options
    *
    * @type {Object}
    *
    * @prop {Array<String|RegExp>} singleTags  Custom single tags (selfClosing)
-   * @prop {String} closingSingleTag Closing format for single tag
+   * @prop {String} closingSingleTag Closing format for single tag @prop
+   * @prop {Boolean} quoteAllAttributes If all attributes should be quoted.
+   * Otherwise attributes will be unquoted when allowed.
    *
    * Formats:
    *
@@ -51,6 +52,10 @@ function render (tree, options) {
   })
 
   var closingSingleTag = options.closingSingleTag
+  var quoteAllAttributes = options.quoteAllAttributes
+  if (typeof quoteAllAttributes === 'undefined') {
+    quoteAllAttributes = true
+  }
 
   return html(tree)
 
@@ -75,7 +80,11 @@ function render (tree, options) {
 
     for (var key in obj) {
       if (typeof obj[key] === 'string') {
-        attr += ' ' + key + '="' + obj[key].replace(/"/g, '&quot;') + '"'
+        if (quoteAllAttributes || obj[key].match(ATTRIBUTE_QUOTES_REQUIRED)) {
+          attr += ' ' + key + '="' + obj[key].replace(/"/g, '&quot;') + '"'
+        } else {
+          attr += ' ' + key + '=' + obj[key]
+        }
       } else if (obj[key] === true) {
         attr += ' ' + key
       } else if (typeof obj[key] === 'number') {
diff --git a/test/render.test.js b/test/render.test.js
index a3407a5..25153f7 100644
--- a/test/render.test.js
+++ b/test/render.test.js
@@ -289,5 +289,58 @@ describe('PostHTML Render', function () {
         expect(render(fixture, options)).to.eql(expected)
       })
     })
+
+    describe('quoteAllAttributes', function () {
+      it('True', function () {
+        var options = { quoteAllAttributes: true }
+
+        var fixture = { tag: 'a', attrs: { href: '/about/me/' } }
+        var expected = '<a href="/about/me/"></a>'
+
+        expect(render(fixture, options)).to.eql(expected)
+      })
+
+      it('False', function () {
+        var options = { quoteAllAttributes: false }
+
+        var fixture = { tag: 'a', attrs: { href: '/about/me/' } }
+        var expected = '<a href=/about/me/></a>'
+
+        expect(render(fixture, options)).to.eql(expected)
+      })
+
+      it('Required Space', function () {
+        var options = { quoteAllAttributes: false }
+
+        var fixture = { 'tag': 'p', 'attrs': { 'id': 'asd adsasd' } }
+        var expected = '<p id="asd adsasd"></p>'
+
+        expect(render(fixture, options)).to.eql(expected)
+      })
+
+      it('Required Tab', function () {
+        var options = { quoteAllAttributes: false }
+
+        var fixture = { tag: 'a', attrs: { href: '/about-\t-characters' } }
+        var expected = '<a href="/about-\t-characters"></a>'
+
+        expect(render(fixture, options)).to.eql(expected)
+      })
+
+      it('Closing slash', function () {
+        var options = {
+          closingSingleTag: 'slash',
+          quoteAllAttributes: false
+        }
+
+        // Note that <area href=foobar/> is incorrect as that is parsed as
+        // <area href="foobar/">.
+
+        var fixture = { tag: 'area', attrs: { href: 'foobar' } }
+        var expected = '<area href=foobar />'
+
+        expect(render(fixture, options)).to.eql(expected)
+      })
+    })
   })
 })