A duvet (from the French duvet "down") or doona is a type of bedding a soft flat bag traditionally filled with down or feathers, or a combination of both and used on a bed as a blanket. Duvets originally came out of rural Europe and were made from the down feathers of the Eider duck, which is well known for its usefulness as an insulator. Duvets reduce the complexity of making a bed, as it is a single covering instead of the combination of sheets, blankets, and quilts or other bed covers, which is traditional in many parts of the world. The cover is called a "duvet cover" or a "quilt cover".

In Australia a duvet is called a "Doona", from a trademarked brand name derived from the Old Norse "dunn" meaning "down feathers". Though still registered to the Tontine company, the name "Doona" has become a generic term for a duvet or down quilt. A duvet is sometimes confused with a comforter, although comforters go on top of the traditional sheets and blankets and are primarily decorative while duvets are used alone.