Having graduated from the Central School of Speech and Drama, she made her professional stage debut at London's Lyric Theatre in The Way of the World alongside Barbara Flynn, with whom she appeared in television's Cranford.
Griffiths has appeared in many television programmes, including Doctor Finlay and Drop the Dead Donkey and playing Janet in The Smoking Room.
In January 2011 she appeared as a frightened passenger in the BBC1 comedy series Come Fly With Me, which is written by Matt Lucas and David Walliams.
Later that year she played several roles, including Beatrix Potter, in Sky's Psychobitches (part of Playhouse Presents), appearing in four episodes.
In February 2017 she appeared as a primary school head teacher Miss Anstis in the BBC sitcom Not Going Out starring Lee Mack and Sally Bretton.