SM or sm may refer to:
Smallpox was an infectious disease caused by one of two virus variants, variola major and variola minor.
Smallville is an American television series developed by writer-producers Alfred Gough and Miles Millar, based on the DC Comics character Superman created by Jerry Siegel and Joe Shuster.
Smosh is an American sketch comedy YouTube channel created by Anthony Padilla and Ian Hecox.
SMS (short message service) is a text messaging service component of most telephone, internet, and mobile-device systems.
SM Entertainment Co., Ltd. (Hangul: SM엔터테인먼트) is Korea's largest entertainment company, founded in 1995 by Lee Soo-man.
A smart card, chip card, or integrated circuit card (ICC) is a physical electronic authorization device, used to control access to a resource.