A futon (布団) is a type of mattress that makes up a Japanese bed.

Japanese futons are flat, about 5cm thick with a fabric exterior stuffed with cotton or synthetic batting. They are often sold in sets which include the futon mattress (shikibuton), a comforter (kakebuton) and pillow (makura). Pillows are generally filled with beans, buckwheat chaff or plastic beads. Futons are designed to be placed on tatami flooring, and are traditionally folded away and stored in a closet during the day to allow the tatami to breathe and to allow for flexibility in the use of the room. Futons should be aired in sunlight regularly, especially if not put away during the day.

Western futons are different from Japanese futons in several ways. They are usually filled with a combination of foam and batting, and are almost always much thicker and larger than Japanese futons, resembling a traditional mattress in size. They are usually placed on a configurable frame for dual-use as a bed and a couch and are a cheap alternative to a bed or other furniture. Such futons are often sold in sets that include the mattress and frame.

Most Japanese people would not recognize a western-style "futon" as a futon.