A pillow is a support of the body at rest for comfort, therapy, or decoration. Pillows are used in different variations by many species, including humans. Some types of pillows include throw pillows, body pillows, decorative pillows, and many more. Pillows that aid sleeping are a form of bedding that supports the head and neck. Other types of pillows are designed to support the body when lying down or sitting. There are also pillows that consider human body shape for increased comfort during sleep. Decorative pillows used on beds, couches or chairs are sometimes referred to as cushions.

In contemporary western culture, pillows consist of a plain or patterned fabric envelope (known as a pillowcase) which contains a soft stuffing, typically synthetic and typically standardized in sizes and shape. Pillows have been historically made of a variety of natural materials and many cultures continue to use pillows made from natural materials in the world.

The word pillow comes from Middle English pilwe, from Old English pyle (akin to Old High German pfuliwi) and from Latin pulvinus. The first known use of the word pillow was before the 12th century.