55

55 may refer to:
 * 55 (number)
 * 55 BC
 * AD 55
 * 1955
 * 2055

Science

 * Caesium, by the element's atomic number

Astronomy

 * Messier object M55, a magnitude 7.0 globular cluster in the constellation Sagittarius
 * The New General Catalogue object NGC 55, a magnitude 7.9 barred spiral galaxy in the constellation Sculptor

Transportation

 * The highest speed limit allowed in the United States between 1974 and 1986 per the National Maximum Speed Law
 * Highway 55, several roads
 * Route 55 (disambiguation), bus and tram routes

Film

 * 55 Days at Peking, a film starring Charlton Heston and David Niven

Other uses

 * Gazeta 55, an Albanian newspaper
 * Agitation and Propaganda against the State, also known as Constitution law 55, a law during Communist Albania
 * +55, the code for international direct dial phone calls to Brazil
 * 5:5, law enforcement code for handcuffs
 * 55 (album), by the Knocks
 * "55", a 2022 song by Raymix
 * "55 (Hamsa oua Hamsine)", an instrumental by the Master Musicians of Joujouka from Brian Jones Presents the Pipes of Pan at Joujouka
 * "Fifty Five", a song by Karma to Burn from the album Arch Stanton, 2014
 * 55 Pandora, a main-belt asteroid