They say that, technically, Star Wars is a Western because of the way the plot and characters are arranged. But genre-wise, the series is usually put into sci-fi, right? Because it takes place partially in space and includes space travel and people from different planets. But I usually think of the Star Wars universe as fantasy.
Rewatching the entire series (starting with the original trilogy, then the prequel trilogy, of course), I started thinking about little things that I liked when I was younger. I liked Tatooine, with its beautiful sky and desert architecture and white linen clothing. I liked all the green on Endor. I liked all the braids in the hairstyles.
This type of thing, it reminds me of some of the things I loved while watching The Lord of the Rings for the first time. The trees and blue lights of Lothlorien, Galadriel's long hair and skirts, the cloaks of the Fellowship, the rolling hills of Rohan. Beautiful and/or fascinating things to look at. That's what fantasy often offers since it portrays a different world, only partially designed after our own. And Star Wars takes place in a galaxy far, far enough away that it might as well be a whole new universe. It has its own rules, system, settings, and people. To me, Tatooine is as fascinating as Lothlorien, if in a completely different way.
Instead of dwarves or fairies or unicorns, there are jawas, wookies, and droids. And instead of magic, there is the Force. Think about something like Harry Potter, where the characters have to learn to use magic, choosing either good or ill as you do with anything in life. That type of journey is not so unlike Luke's and Anakin's journeys toward understanding their power. They can levitate things with their minds, after all; that's more fantasy than science.
Maybe it's also because the space element is engrained in the Star Wars world that it feels more like fantasy than sci-fi. We're not dealing with a future version of our world where Earth has gained space travel; we're dealing with a different territory where space travel is just one of the facts of existence. Isn't fantasy wonderful?