Hoon is a derogatory term used in Australia and New Zealand, to refer to a anyone who engages in loutish, anti-social behaviours. In particular, it is used to refer to one who drives a car or boat in a manner which is anti-social by the standards of contemporary society, that is, fast, noisily or dangerously. In New Zealand, the term "boy racer" is also widely used. Another slang term, revhead—derived from "rev", an alternate term for RPM—is sometimes used in place of hoon. However, "revhead" can refer to any car enthusiast, while hoon is always pejorative. "Anti-hoon laws", while they generally concern road vehicles, sometimes also target anti-social behaviour in motor boats.

Hoon activities can include speeding, burnouts, doughnuts or screeching tires. Those commonly identified as being involved in "hooning" or street racing are young and predominantly male, although increasingly female, drivers in the age range of 17 and 35 years.

Hoon control laws are beginning to be extended to dangerous and annoying hoon behaviour using boats and other vessels, particularly jet skis. The State of Victoria, Australia passed legislation in late 2009 to control hoon activities using recreational vessels.