English novelist especially noted for two series of mysteries: one featuring medieval monastics in Britain and the other featuring a modern family.

Peters worked as a pharmacist's assistant during the 1930s and served in the Women's Royal Navy Service from 1940 to 1945. Beginning in the mid-1930s she wrote historical fiction and crime novels, using her own name and several pseudonyms. Though her first crime novel, Murder in the Dispensary, was published in 1938 (under the name Jolyon Carr), for most of the next 20 years she concentrated on other genres. She Goes to War (1942) is based on her experiences in military service. Under her own name she published the mystery Fallen into the Pit (1951), featuring 13-year-old Dominic Felse. In Death and the Joyful Woman (1961), he returns as a 16-year-old whose girlfriend is connected with murder; the novel, like the many Felse family mysteries that followed it, was published under the name Ellis Peters.

Peters's interest in Shropshire history led her to write the mystery A Morbid Taste for Bones (1977), set in the 12th century. It features the monk and herbalist Brother Cadfael, who before taking his vows had been a lover, sailor, soldier, and fighter in the First Crusade. He returns in One Corpse Too Many (1979), and in the 1980s and '90s Peters published 18 Cadfael novels and one book of stories featuring Cadfael. They include The Virgin in the Ice (1982) and The Heretic's Apprentice (1989). Many of the Cadfael mysteries were adapted for television, featuring Derek Jacobi in the title role. Under her own name Peters wrote crime and historical fiction, including the four-volume Brothers of Gwynedd series (1974–77), and translated more than a dozen volumes of prose and poetry from Czech and Slovak into English. She was made an Officer of the Order of the British Empire in 1994.