Yes, you can put roof racks on a Highlander. There are a few different ways to do this, depending on what kind of roof rack you have. If you have the factory roof rack that came with your Highlander, then you can simply use the included crossbars to attach your roof rack. If you have aftermarket crossbars, then you will need to use either the U-bolt or clamp method to attach them to your vehicle. Whichever method you use, make sure that your crossbars are evenly spaced and securely attached before loading anything onto them.