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.
SMS (short message service) is a text messaging service component of most telephone, internet, and mobile-device systems.
Smosh is an American sketch comedy YouTube channel created by Ian Andrew Hecox (born November 30, 1987) and Daniel Anthony Padilla (; born September 16, 1987).
A smart card, chip card, or integrated circuit card (ICC), is any pocket-sized card that has embedded integrated circuits.