<p dir="auto">Would be a good addition to the current Select. Found this old Issues (<a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="187741783" data-permission-text="Title is private" data-url="https://github.com/mui/material-ui/issues/5521" data-hovercard-type="issue" data-hovercard-url="/mui/material-ui/issues/5521/hovercard" href="https://github.com/mui/material-ui/issues/5521">#5521</a>) for this feature but nothing happend yet.</p>
<p dir="auto">Maybe something like this</p>
<div class="highlight highlight-source-diff notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="&lt;Select&gt;
+    &lt;MenuGroup label=&quot;optgroup label&quot;&gt;
        &lt;MenuItem value={10}&gt;Ten&lt;/MenuItem&gt;
        &lt;MenuItem value={20}&gt;Twenty&lt;/MenuItem&gt;
        &lt;MenuItem value={30}&gt;Thirty&lt;/MenuItem&gt;
+    &lt;/MenuGroup&gt;
&lt;/Select&gt;"><pre class="notranslate">&lt;Select&gt;
<span class="pl-mi1"><span class="pl-mi1">+</span>    &lt;MenuGroup label="optgroup label"&gt;</span>
        &lt;MenuItem value={10}&gt;Ten&lt;/MenuItem&gt;
        &lt;MenuItem value={20}&gt;Twenty&lt;/MenuItem&gt;
        &lt;MenuItem value={30}&gt;Thirty&lt;/MenuItem&gt;
<span class="pl-mi1"><span class="pl-mi1">+</span>    &lt;/MenuGroup&gt;</span>
&lt;/Select&gt;</pre></div>
<p dir="auto"><a href="https://www.w3schools.com/tags/tag_optgroup.asp" rel="nofollow">https://www.w3schools.com/tags/tag_optgroup.asp</a></p>
<p dir="auto">Please add feature like this<br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/590985/12009278/9c3fc174-ac82-11e5-9a31-2d916aeace55.png"><img src="https://cloud.githubusercontent.com/assets/590985/12009278/9c3fc174-ac82-11e5-9a31-2d916aeace55.png" alt="image" style="max-width: 100%;"></a></p>