G4

G4 or G.IV may refer to:

Places

 * County Route G4 (California), a county highway in Santa Clara County, California, USA
 * G4 Beijing–Hong Kong and Macau Expressway, an expressway in China
 * G4 (Taichung Metro), also known as Songzhu Station or Jiushe Station, a station under construction in the Taichung Metro

Arts, entertainment, games, media

 * G4 (American TV network), an American television channel
 * G4 (Canadian TV channel), a former Canadian television channel
 * G4 (group), a British vocal troupe
 * Grob's attack, an opening move in chess

Groups, organisations, companies

 * G4 nations, four nations that support each other's bids to become permanent members of the United Nations Security Council: Brazil, Germany, India, and Japan
 * Big Four (Western Europe), sometimes called 'G4', a group of powerful countries in Europe
 * VIP Protection Unit, a unit of the Hong Kong Police Force (originally Section G, Division 4)
 * Allegiant Air, by IATA airline designator

Electrics, electronics, and computing

 * G4, a type of bi-pin lamp base (socket), a lamp fitting where the pin spacing is 4mm
 * LG G4 smartphone
 * Moto G4, a line of smartphones
 * Group 4 compression, a type of image compression used in fax machines and some image file formats

Apple Computer

 * PowerPC G4, a type of microprocessor by Freescale used by Apple
 * Power Mac G4, a series of personal computers made by Apple Inc in July 1999
 * PowerBook G4, a series of Professional notebooks made by Apple Inc in 2001
 * iMac G4, a series of personal computer made by Apple Inc in January 2002
 * Xserve G4, an Xserve server made by Apple Inc in May 2002
 * iBook G4, an iBook series of consumer notebooks in October 2003
 * Mac Mini G4, a Mac Mini series of ultracompact computer in January 2005

Vehicles

 * AEG G.IV, a German World War I heavy bomber
 * Caudron G.4, a 1915 French biplane
 * Friedrichshafen G.IV, a 1918 German medium bomber
 * Gotha G.IV, a 1916 German heavy bomber
 * Gulfstream IV, a family of private jet aircraft
 * Mitsubishi G4M "Betty", a World War II Japanese fast bomber
 * Soko G-4 Super Galeb, a jet trainer/light attack jet of Yugoslav origin
 * USS G4 (SS-26), a 1914 G-class submarine of the United States Navy
 * G4-class freighter, a cargo ship design
 * LNER Class G4, a class of British steam locomotives
 * Pontiac G4, a compact car sold in Mexico

Other uses

 * G4 EA H1N1, a strain of influenza
 * G-quadruplex, a DNA secondary structure
 * Group 4 element, a class of elements on the Periodic Table
 * ATC code G04 Urologicals, a subgroup of the Anatomical Therapeutic Chemical Classification System
 * Galactic 04 (G04), a Virgin Galactic suborbital tourist spaceflight in October 2023, the first spaceflight of a Pakistani