E8

E8 may refer to:

Mathematics

 * E8, an exceptional simple Lie group with root lattice of rank 8
 * E8 lattice, special lattice in R8
 * E8 manifold, mathematical object with no smooth structure or topological triangulation
 * E8 polytope, alternate name for the 421 semiregular (uniform) polytope
 * Elementary abelian group of order 8

Physics

 * E8 Theory, term sometimes loosely used to refer to An Exceptionally Simple Theory of Everything

Transport

 * E-8 Joint STARS, a retired USAF command and control aircraft
 * EMD E8, 1949 diesel passenger train locomotive
 * European route E8, part of the international E-road network, running between Tromsø, Norway and Turku, Finland
 * European walking route E8, a walking route from Ireland to Turkey
 * HMS E8, 1912 British E class submarine
 * London Buses route E8, runs between Ealing Broadway station and Brentford
 * Mikoyan-Gurevich Ye-8, 1962 supersonic jet fighter developed in the Soviet Union
 * E8, IATA code for the former Alpi Eagles airline
 * E8, IATA code for City Airways
 * Spyker E8, Spyker Cars model
 * Hokuriku Expressway, route E8 in Japan
 * East Coast Expressway and Kuala Lumpur–Karak Expressway, route E8 in Malaysia
 * E8 Series Shinkansen, a Japanese high-speed train to be introduced in 2024

Other uses

 * Empire 8, intercollegiate athletic conference affiliated with the NCAA's Division III
 * E-8 (rank), an enlisted rank in the military of the United States
 * E8, baseball scorekeeping abbreviation for an error on the center fielder
 * E8, postcode district in the London E postcode area