Stephen Gallagher (born 13 October 1954) is an English writer.
Gallagher was born in Salford, Greater Manchester. He has written several novels and television scripts, including for the BBC television series Doctor Who — for which he wrote two serials, Warriors' Gate (1981) and Terminus (1983)—as well as for the series Rosemary & Thyme and Bugs, for two seasons of which he was script consultant along with Brian Clemens. He adapted his own novel Chimera for ITV and directed the adaptation of Oktober as well as writing the feature-length episode The Kingdom of Bones for the BBC series Murder Rooms.
He also developed and wrote a science-based series for ITV, Eleventh Hour, starring Patrick Stewart as a government science investigator and advisor. The programme was rumoured to be ITV's answer to the new series of Doctor Who, but was more in the tradition of the hard-science thriller. Gallagher's series format was acquired for a US television remake by the CSI trio of CBS, Jerry Bruckheimer TV and director Danny Cannon. The series aired on CBS and starred Rufus Sewell and Marley Shelton.
Life Line, broadcast in 2007, was a two-part a supernatural mystery starring Ray Stevenson, Joanne Whalley and Jemima Rooper.
Stephen Gallagher was lead writer and story supervisor on NBC's 13-part series Crusoe, screened in 2008/2009, and contributed two episodes to the US version of Eleventh Hour including Medea, the season finale. In 2009 He served as Co-Executive Producer on Bruckheimer's crime show The Forgotten, starring Christian Slater. The Legacy, a two-part story for season 16 of the BBC's Silent Witness, was Best Drama winner in the 2014 European Science TV and New Media Awards.