Cath may refer to:
- a Catholic
- Cautha, a sun god in Etruscan mythology
- Catheter or catheterization
- The Irish word for a battle
- A protein structure classification CATH
- A female name, a shortened form of Catherine or Cathryn, akin to "Cathy" and "Cat." It is unusual for it to be used as a surname, with only one family in the UK (with members in the USA), another family in New York state, USA, that could be related to the UK one; and a Dutch family that only took the name in 1811, when Napoleon made all families take a surname instead of using patronymics.
