31

31 may refer to:


 * 31 (number)

Years

 * 31 BC
 * AD 31
 * 1931 CE ('31)
 * 2031 CE ('31)

Music

 * Thirty One (Jana Kramer album), 2015
 * Thirty One (Jarryd James album), 2015
 * "Thirty One", a song by Karma to Burn from the album Wild, Wonderful Purgatory, 1999

Science

 * Gallium, a post-transition metal in the periodic table
 * 31 Euphrosyne, an asteroid in the asteroid belt
 * (31) Euphrosyne I, a satellite of 31 Euphrosyne

Film and television

 * 31 (film), a 2016 horror film
 * 31 (Kazakhstan), a television channel
 * 31 Digital, an Australian video on demand service

Transportation

 * 31st (CTA station), a rapid transit station in Chicago
 * 31 (MBTA bus), a bus route in Boston, Massachusetts
 * 31 (RIPTA), a bus route in Rhode Island

Other uses

 * Thirty-one (card game)