Sunboard or Foam board is a strong, lightweight, and easily cut sheet material commonly used for mounting vinyl prints, backing in framing, and painting. It typically has three layers: an inner layer of polystyrene foam sandwiched between white clay-coated paper on the outside.

In addition to printing, Sunboard is often used for prototyping objects, producing architectural models, and creating casting patterns. Hobbyists frequently use it to create backgrounds for scale model displays, dioramas, and computer game settings. Photographers find it useful as a light reflector in studios, and designers use it to display presentations of new products. Aero-modellers also use it to build small radio-controlled aircraft.

Today, Sunboard is widely used in India and globally for large format printing and store branding. Photos or creative designs are printed on self-adhesive vinyl and then mounted onto the Sunboard. The Sunboard can then be affixed to walls, pillars, or other flat surfaces using double-sided adhesive tapes or nails, depending on the surface. A more modern method involves printing directly onto the Sunboard using a UV flatbed printing machine. UV prints on Sunboard last longer and are free from peeling problems.