SM4

SM4, Sm4 or SM-4 may refer to:


 * SM4 (cipher), a block cipher used in the Chinese National Standard
 * SM4 (classification), a swimming classification
 * VR Class Sm4, a type of train operated by the VR Group
 * HST-SM4, the final servicing mission to the Hubble Space Telescope
 * Standard Missile 4, a missile
 * SM4, a part of the SM postcode area, in Sutton, England
 * SM-4, minicomputer