An underwear store is a clothing store which specializes in items worn under the visible clothing, including lingerie, negligees, nightgowns, bath robes, panties, bras, stockings, briefs, boxer shorts, and thermal underwear. Many but not all stores in this category specialize in erotic, semi-erotic, or fashionable styles of underwear.

The assortment includes undergarments and the associated intimate, night, and lounge clothing named above. A store can therefore carry robes or nightgowns as well as garments normally hidden beneath outer clothing.

Erotic or fashionable presentation is optional within this specialization. A beachwear store is identified by clothing for beaches and aquatic recreation, even when swimwear has a similar outline to some undergarments.