E3 (disambiguation)

E3, E.III, E03, E-3 or E³ can refer to:

In sports and games:
* E3 Prijs Vlaanderen (English: E3 Prize Flanders), a professional cycling race held in Belgium
* E3, one of the European long-distance paths

In military:
* E-3 Sentry, an AWACS aircraft based on the Boeing 707
* Fokker E.III, a 1915 Dutch fighter aircraft
* HMS E3, an E-class submarine of the British Royal Navy
* Pfalz E.III, a German aircraft powered by the Oberursel U.I engine
* Siemens-Schuckert E.III, a German aircraft powered by the Oberursel U.I engine
* E-3 (rank), a paygrade in the United States Military

In organizations:
* E3 Media and Business Summit (formerly known as the Electronic Entertainment Expo), a yearly computer and video game expo and conference
* E3, Germany, United Kingdom and France, the three nations with the largest populations and economies within the European Union

In places:
* London E3, the postal code for Bow in London

In science and technology:
* E3 binding protein, a protein
* E-3 process, an obsolete development process associated with photographic transparency film
* e3 (text editor), a text editor
* Honda E3, a 1991 Honda E series ASIMO predecessor robot
* Olympus E-3, a digital SLR camera
* E3, a clade of the human Y-chromosome DNA haplogroup E
* E3, a communications channel defined in the E-carrier standard
* E³.series, electrical CAD software
* Dihydrolipoamide dehydrogenase, the third element of the pyruvate dehydrogenase complex

In transportation:
* E3 National Highway, a National Highways of Pakistan
* E3 Series Shinkansen, a Japanese high-speed train
* EMD E3, a diesel locomotive
* European route E03, a
* LB&SCR E3 Class, a 1894 British class of steam locomotives
* London Buses route E3, a bus route in London
* Mazda E engine#E3
* PRR E3, an American and also :
* Domodedovo Airlines IATA airline designator

In other:
* E-3 visa, a non-immigrant visa allowing Australian citizens to live and work in the United States
* E03 : Other hypothyroidism code