Born in London, Emma Tennant was educated at St Paul's Girls' School and spent the World War II years and her childhood summers at the family's faux Gothic mansion The Glen in Peeblesshire. Her family also owned estates in Trinidad.
Tennant grew up in the modish London of the 1950s and 1960s. She worked as a travel writer for Queen magazine and an editor for Vogue, publishing her first novel, The Colour of Rain, under a pseudonym when she was twenty-six. Between 1975 and 1979, she edited a literary magazine, Bananas, which helped launch the careers of several young novelists.
A large number of books by Tennant followed: thrillers, children's books, fantasies, and several revisionist takes on classic novels, including a sequel to Pride and Prejudice called Pemberley. In later years, she began to treat her own life in such books as Burnt Diaries (1999), which details her affair with Ted Hughes.
Tennant has been married four times, including to the journalist and author Christopher Booker and the political writer Alexander Cockburn. She has two daughters and a son, author Matthew Yorke. In April 2008, she married her partner of 33 years, Tim Owens. She died in 2017.