Oman attracts the whole world by its traditional attire for the men's hand-stitched Dishdasha (Long Shirt). Which are mostly in white colour as a formal dress and there are lots of other colours available for the Dishdasha. Which comes under informal attire. The most common fabrics such as cotton, silk and polyester are use to stitch a very comfortable and elegant Omani dishdasha.
The locals also cover their head with a beautiful hand made cap called Kuma or turban which called Mussar as a complete part of traditional dress.
I always recommend my guests to wear traditional attire of Oman.
People of Oman are very respective and guest-friendly.