A whiteboard (also known by the terms markerboard, dry-erase board, dry-wipe board, pen-board, and the misnomer greaseboard) is a name for any glossy, usually white surface for nonpermanent markings. Whiteboards are analogous to chalkboards, allowing rapid marking and erasing of markings on their surface. The popularity of whiteboards increased rapidly in the mid-1990s and they have become a fixture in many offices, meeting rooms, school classrooms, and other work environments.

The term whiteboard is also used metaphorically to refer to features of computer software applications that simulate whiteboards. Such "virtual whiteboards" allow one or more people to write or draw images on a simulated canvas. This is a common feature of many virtual meeting, collaboration, and instant messaging applications. The term whiteboard is also used to refer to interactive whiteboards.

The first whiteboards were very expensive and were made of an enameled steel. Cheaper alternatives have since made their way into the market, including laminated chipboard, high pressure laminates and steel boards with a white, usually polyester or acrylic, coating. Enameled whiteboards, also referred to as porcelain, or sometimes even glass boards, remain the highest quality boards available though, since the alternatives all have a tendency to leave residue of erased markings on and in the surface and are difficult to keep clean after a short while. Hard baked vitreous enamel is so non-porous that marker ink does not penetrate the surface and these board remain erasable for life if not scratched. Due to the price difference the cheaper alternatives now have the largest market share in the office products market, but in more demanding environments, such as schools, universities, etc. porcelain boards remain the gold standard.

Other types of dry marker boards are also available, such as high gloss vinyl and coated paper, which can be rolled up, high density two-part high gloss paints, glass and coated acrylics, particularly popularized by TV series and movies.

Clear marker surfaces, made of glass or specially coated acrylic, also appeared on the market about 2007 and were popularized by TV and movies.