A Comforter (in American English), also known as a doona in Australian English, or a continental quilt (or simply quilt) or duvet in British English, is a type of bedding made of two lengths of fabric or covering sewn together and filled with insulative materials for warmth, traditionally down or feathers, wool or cotton batting, silk, or polyester and other down alternative fibers. Like quilts, comforters are generally laid over a top bed sheet (and sometimes also blankets). Duvets are another form of quilt, traditionally filled with feathers, though since the late 20th century often made of synthetic fibres or down alternatives.

A Comforter is sometimes covered for protection and prolonged use. Comforter covers are similar in principle to pillowcases, usually closed with zippers or buttons.

In the United Kingdom the term Comforter is not generally used. It is instead called a quilt (or continental quilt), duvet or an eiderdown. A duvet differs in that it is thicker and usually used without blankets or extra sheets.

Sometimes a Comforter is sold as part of a "bed in a bag", usually a case of some sort with handles that contains an entire set of bedding in the same or a matching pattern: comforter and top sheet, fitted sheet, pillowcase(s), and perhaps pillow sham(s). Some sets have a duvet and duvet cover (more popular in Europe) in place of a comforter and top sheet. More deluxe sets may include a bed skirt and pillows.

Comforters are usually used in the winter season when it is very cold. Due to the thickness of a comforter or the amount of down/feathers or other filling it has, a person is insulated against cold.