Ugg boots, also spelle ugh boots and ug boots, are a style of sheepskin boot, with wool as the inner lining and a tanned outer surface worn by both men and women. Ugg boots often have a synthetic sole, although this is not universal. Uggs are popular with the teenage set, worn by girls with mini skirts, leggings, and with jeans tucked into the boots. Ugg boots are also popular with boys, wearing jeans or tracksuit bottoms inside them most commonly.