Films:
* The French Lieutenant's Woman (1981) - Anne, the "real" woman who inspires the story.
* The Jewel in the Crown (1984) - Sarah Layton, a British woman who falls in love with an Indian man.
* The Remains of the Day (1993) - Miss Kenton, the housekeeper who leaves Darlington Hall.
* The Importance of Being Earnest (2002) - Lady Bracknell.
* The Constant Gardener (2005) - Tessa Quayle, a committed activist who investigates her husband's death.
* The King's Speech (2010) - Queen Mary, the mother of King George VI.
* The Woman in Black (2012) - Alice Drablow, a woman who haunts the house.
* The Imitation Game (2014) - Joan Clarke, a woman who works with Alan Turing to break the Enigma code.
* The Death of Stalin (2017) - Pelageya Volkova, Stalin's personal secretary.
Television:
* The Jewel in the Crown (1984) - (miniseries)
* The Old Curiosity Shop (1985) - (miniseries)
* The Tenant of Wildfell Hall (1996) - (miniseries)
* The Way We Live Now (2001) - (miniseries)
* Poirot (2001) - (episode "The Mystery of the Blue Train")
* Cranford (2007) - (miniseries)
* Inspector Lewis (2010) - (episode "The Dead of Winter")
* The Crown (2016-present) - (recurring role as Anne, Princess Royal)
* Vanity Fair (2018) - (miniseries)
* The Stranger (2020) - (miniseries)
* The Serpent (2021) - (miniseries)
This is just a selection of her work. Diana Quick has appeared in numerous other films, television shows, and plays throughout her career.