Worlds Largest Spider! The Giant huntsman spider is huge, but not deadly to humans. Biggest in the world, the Giant Huntsman Spider was just recently discovered in 2001 in a Cave in Laos. Their torso averages about 2 inches long but it's their leg-span which earn them the title as the biggest spider in the world as they can extend to 12 inches long which is about the size of this dinner plat