According to Guinness World Records, the largest spider in the world is the Goliath bird-eating spider. The males of this species have an average leg span of 11 inches. They are considered a type of tarantula.
Other contenders for the title include the giant huntsman spider, whose body can grow up to a foot in length with a leg span of 6 inches, and the Brazilian salmon pink birdeater, a close relative of the Goliath with a 10-inch leg span. Although its size and name implies that it primarily goes after small birds, the Goliath bird-eating spider actually has a diet similar to less gigantic spiders, feeding mostly upon insects.