- Source: G21
G21 may refer to:
BMW 3 Series (G21), an automobile
County Route G21 (California)
Glock 21, a firearm
Gribovsky G-21, a Soviet aircraft
Grumman G-21 Goose, an American aircraft
Ginetta G21, an automobile produced by Ginetta Cars
G21 developing nations, a trade bloc also known as G20 developing nations