The cat o' nine tails is a type of multi-tailed whipping device.
Cat o' nine tails may also refer to:
- Typha latifolia, the Cat O' Nine Tails plant
- The Cat o' Nine Tails, a 1971 Italian giallo thriller film
- Cat O' Nine Tails, a 1988 composition for string quartet by John Zorn
- Cat O'Nine Tales, a 2006 collection of short stories by Jeffrey Archer
- Cat O'Nine Tails (novel), a 2009 novel by Julia Golding