Boardshorts (occasionally in British English, swim shorts) are a style of men's and, recently, women's summerwear. They were originally developed for aquatic sports, specifically for surfing, but in more recent years they have grown in popularity outside of these sports, and have become a popular form of general beach and summerwear.

The name of "boardshorts" originates from their affiliation with aquatic sports that use a board, such as surfing. They are sometimes called "boardies" in slang, especially in Australia, and "baggies" in South Africa.

Boardshorts are especially popular in North America and spread beyond surfing especially as the skater punk fashion trend got underway. They are also typically worn in men's beach volleyball. They are less popular in other parts of the world, where other suit styles are preferred.

Boardshorts are designed to be quick-drying, and are generally made from smooth polyester or nylon material. They are durable and hold up to wear from contact with a surfboard, yet are comfortable and light-weight. They are well-adapted to their use in various active watersports.