Mary Flora Bell (born 26 May 1957) is a British woman who, as a child, strangled to death two little boys in Scotswood, an inner-city suburb of Newcastle upon Tyne. She was convicted in December 1968 of the manslaughter of the two boys, Martin Brown (aged four) and Brian Howe (aged three). Bell was 11 when she was convicted for killing Brown and Howe.

Since her release from prison in 1980, she has lived under a series of pseudonyms. Her identity has been protected by a court order, which has also been extended to protect the identity of her daughter. In 1998, Bell collaborated with Gitta Sereny on an account of her life, in which she details the abuse she suffered as a child at the hands of her mother, a prostitute, and her mother's clients.

On 25 May 1968, the day before her 11th birthday, Mary Bell strangled four-year-old Martin Brown in a derelict house. She was believed to have committed this crime alone. Between that time and a second killing, she and a friend, Norma Joyce Bell (1955–89; no relation), aged 13, broke into and vandalised a nursery in Scotswood, leaving notes that claimed responsibility for the killing. The police dismissed this incident as a prank.

Mary Flora Bell (born 26 May 1957) is a British woman who, as a child, strangled to death two little boys in Scotswood, an inner-city suburb of Newcastle upon Tyne. She was convicted in December 1968 of the manslaughter of the two boys, Martin Brown (aged four) and Brian Howe (aged three). Bell was 11 when she was convicted for killing Brown and Howe.