Cath may refer to:
- a Catholic
- Cautha, a sun god in Etruscan mythology
- Catheter or catheterization
- the Irish word for a battle
- the Welsh word for a cat
- Cath Palug, a feline creature in Welsh mythology
- CATH, protein structure classification
- Catherine (disambiguation) or Cathryn, colloquially
- Cath..., a Death Cab for Cutie song found on Narrow Stairs