Monica Mayhem (born March 14, 1978) is an Australian pornographic actress and exotic dancer.

Mayhem was born in Brisbane, Australia. Before adult films, Mayhem worked in Sydney and London, first in finance then as an exotic dancer. All of her current work has been for the American adult film industry since December 2000. She has been featured in more than 360 hardcore and softcore adult films and magazines. Outside her the adult business, she is a singer/guitarist in an all-girl metal band, Sweet Avenge. In 2008, she scored a bit part acting on the blockbuster movie version of the long running TV series Sex and the City. She stars as a highly sexed neighbour to Samatha.