91

91 may refer to:

Years

 * 91 BC
 * AD 91
 * 1991
 * 2091
 * etc.

Transportation

 * List of highways numbered
 * 91/Perris Valley Line, a commuter rail line
 * Saab 91, an aircraft

Other uses

 * 91 (number)
 * 91:an, a Swedish comic
 * '91, a 2017 album by Jamie Grace
 * Ninety One (group), a Kazakh boy group
 * Ninety-One (solitaire)
 * Ninety One plc, an Anglo-South African asset management business
 * Protactinium, atomic number 91
 * 91 Aegina, a main-belt asteroid