Tamsin Margaret Mary Greig is a British actress. She is known for both dramatic and comedic roles. She played Fran Katzenjammer in the Channel 4 sitcom Black Books, Dr Caroline Todd in the Channel 4 sitcom Green Wing, Beverly Lincoln in British-American sitcom Episodes and Jackie Goodman in the Channel 4 sitcom Friday Night Dinner. Other roles include Alice Chenery in BBC One's comedy-drama series Love Soup, Debbie Aldridge in BBC Radio 4's soap opera The Archers, Miss Bates in the 2009 BBC version of Jane Austen's Emma, and Beth Hardiment in the 2010 film version of Tamara Drewe. In 2020, Greig starred as Anne Trenchard in Julian Fellowes' ITV series Belgravia.

Black Books is a British sitcom created by Dylan Moran and Graham Linehan, and written by Moran, Kevin Cecil, Andy Riley, Linehan and Arthur Mathews. It was broadcast on Channel 4, running for three series from 2000 to 2004. Starring Dylan Moran as Bernard Black, Bill Bailey as Manny Bianco, and Tamsin Greig as Fran Katzenjammer, the series is set in the eponymous London bookshop and follows the lives of its owner, his assistant, and their friend. The series was produced by Big Talk Productions, in association with Channel 4.