This can be used in a parent or child but it’s particularly helpful for child themes where the parent has more sidebars than you need.

 
<?php 
// This is amazingly helpful for child themes. 
function remove_sidebar() { 
<span style="white-space: pre;"> </span>unregister_sidebar('SIDEBAR_ID'); 
} 
 
add_action( 'admin_init', 'remove_sidebar'); 
?>