Lyttelton Stewart Forbes Winslow MRCP (31 January 1844 – 8 June 1913) was a British psychiatrist famous for his involvement in the Jack the Ripper and Georgina Weldon cases during the late Victorian era.

Other trials in which Winslow was involved were those of Percy Lefroy Mapleton, convicted of the murder on the Brighton line; that of Florence Maybrick, and that of Amelia Dyer, the Reading baby farmer.

[8] Winslow managed his father's asylums after his death in 1874, but these were removed from his control following a family feud, so he turned his attention to forensic work.

[9] Winslow's suspect was Canadian G. Wentworth Smith, who had come to London to work for the Toronto Trust Society, and who lodged with a Mr and Mrs Callaghan at 27 Sun Street, Finsbury Square.

Callaghan went to Winslow to express his suspicions, and he in turn contacted the police, who fully investigated his theory and showed it to be without foundation.

Nevertheless, convinced that he was correct, for many years Winslow declared his theory at every chance, and claimed that his actions were responsible for forcing Jack the Ripper into abandoning murder and fleeing the country.

[9] When Winslow's claims about knowing the identity of the Ripper were reported in the English press Scotland Yard sent Chief Inspector Donald Swanson to interview him.

[11] He gained further publicity, and visited New York City in August 1895, to chair a meeting on lunacy at an International Medico-Legal Congress.

[14] His older brother was Edward Winslow Forbes, the vicar of Epping, while his sister, Susanna Frances, married the humourist Arthur William à Beckett.

Winslow appears as the central figure in the 2003 novel A Handbook for Attendants on the Insane,[16] since republished in a new edition as The Revelation of Jack the Ripper by Alan Scarfe.