I4

I4, i4, I 4 or I-4 may refer to:

Arts, entertainment, and media

 * I-4: Loafing and Camouflage, a Greek film

Military

 * 1st Life Grenadier Regiment (Sweden) (1816–1927), a Swedish infantry regiment
 * JAPANESE SUBMARINE I-4, a World War II Type J1 submarine of the Imperial Japanese Navy
 * Life Grenadier Regiment (Sweden) (1928–1997), a Swedish infantry regiment
 * Tupolev I-4, a 1927 Soviet aircraft

Science and technology

 * I-4 satellite
 * i4, an integer in XML-RPC
 * Industrie 4.0, the fourth Industrial Revolution

Transportation

 * I4 engine, a piston engine
 * Interstate 4, an interstate highway in Florida
 * BMW i4, a German mid-size electric sedan
 * Interstate Airlines, by IATA airline designator
 * LB&SCR I4 class, a British locomotive