Stargate (also known Defender II) is an arcade game released in 1981 by Williams Electronics. Created by Eugene Jarvis and Larry DeMar, it is a sequel to the 1980 game Defender, and was the first of only three productions from Vid Kidz, an independent development house formed by Jarvis and DeMar.

This sequel adds new ships to the alien fleet, including Firebombers, Yllabian Space Guppies, Dynamos, and Space Hums. The Defender ship is now equipped with an Inviso cloaking device, which renders the ship invulnerable when activated, but has a limited charge. A Stargate transports the ship to any humanoid in trouble. There are two special stages: the Yllabian Dogfight, first appearing at wave 5 and recurring every 10 waves; and the Firebomber Showdown, first appearing at wave 10 and also recurring every 10 waves.