The Universal Media Disc (UMD) is a discontinued optical disc medium developed by Sony for use on its PlayStation Portable handheld gaming and multimedia platform. It can hold up to 1.8 gigabytes of data and is capable of storing video games, feature-length films, and music. UMD is the trademark of Sony Computer Entertainment for their optical disk cartridge (ODC).

An optical disc is a flat, usually disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to be detected on the other side.