Denn may refer to:

DENN, the NASDAQ ticker symbol for Denny's Denn, County Cavan, a parish in County Cavan, Ireland Denn GFC, a Gaelic Athletic Association club in County Cavan, Ireland

People with the surname Matthew Denn (born 1966), American lawyer and politician Robert Denn, English cricketer

See also Den (disambiguation) Cavan, Ireland