A cork hat (also known as a Hobbly-Bob) is a type of headgear with corks strung from the brim, to ward off insects.
Believed by some to have been worn by jackaroos and swagmen in the blow-fly infested Australian outback, the cork hat has become part of the stereotypical, almost mythical, representation of the Australian ocker, particularly in the United Kingdom. The shape and material of cork hats vary, though typically they are shaped similar to a slouch hat. Pieces of cork, often shaped as bottle stoppers, are hung on string from the brim of the hat. The low density of cork means a number of pieces may hang from a hat without significantly increasing its weight. Movement of the head causes the corks to swing, discouraging insects from swarming around the wearer's head. In modern times the cork hat is virtually never seen and is little more than a novelty item. Further there is little evidence to indicate that its use in previous eras was any more common or widespread.