G4

G4 or G.IV may refer to:

Transport

AEG G.IV, a German World War I heavy bomber
Allegiant Air, by IATA airline designator
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
County Route G4 (California), a county highway in Santa Clara County, California, USA
G4 Beijing–Hong Kong–Macau Expressway, an expressway in China and Hong Kong
- G4W Guangzhou–Macau Expressway, a spur expressway from Guangzhou to Macau
G4 (Taichung Metro), also known as Songzhu Station or Jiushe Station, a station under construction in the Taichung Metro

Group 4 element, a class of elements on the Periodic Table
ATC code G04 Urologicals, a subgroup of the Anatomical Therapeutic Chemical Classification System
G4, a type of bi-pin lamp base (socket), a lamp fitting where the pin spacing is 4mm
LG G4 smartphone

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
Group 4 compression, a type of image compression used in fax machines and some image file formats

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
G4 (EU), a group of powerful countries in the European Union
VIP Protection Unit, a unit of the Hong Kong Police Force (originally Section G, Division 4)