Yabby or Yabbie is a name given in Australia to two different kinds of crustacean.
- A freshwater yabby is a crayfish of the genus Cherax. They are often caught for food. They are found in dams, ponds, lakes and rivers in Australia's Eastern States.
- A marine yabby is a ghost shrimp, which lives in deep burrows in the intertidal zone. They are used as bait for fishing, especially in Queensland and northern New South Wales. A common species in south-eastern Australia is the Bass yabby, Trypaea australiensis.