Brian Michael Downey (born 27 January 1951, in Dublin, Ireland), is an Irish drummer.

He is best known for co-founding the rock band Thin Lizzy; along with bassist-singer Phil Lynott, he was the only constant member of the pioneering hard rock group. Downey also co-wrote many Thin Lizzy songs. Critic Ed Rivadavia argues that Downey was "certainly one of the most underrated [rock drummers] of his generation."

Before forming Thin Lizzy, Downey and Lynott were in numerous bands together, including The Black Eagles and Orphanage. Upon meeting guitarist Eric Bell, the trio formed Thin Lizzy. For the next thirteen years Downey was the band's permanent drummer, as well as drumming on Lynott's solo albums. He was originally to play drums for Grand Slam, Lynott's band after Lizzy, but opted out due to personal problems with the band's music and the people Lynott became associated with. After Lynott's death Downey played in the tribute Thin Lizzy lineup with John Sykes, Scott Gorham, Darren Wharton and Marko Mendoza but has been absent from recent Lizzy touring lineups.

He was a guest at the unveiling of Phil Lynott's statue, and drummed for Gary Moore at the tribute concert that followed. Brian has also appeared on Gary's latest album, 2007's Close As You Get and subsequent tour.

Brian Downey (born October 31, 1944, in Newfoundland, Canada) is an actor perhaps best-known for his portrayal of Stanley Tweedle, the selfish, lecherous, incompetent security guard (fourth class) who finds himself in control of the enormously powerful, eponymous spaceship in the science-fiction television series LEXX.

Additionally, Downey is a character actor who has appeared in various films and guest starring roles on TV, including a recurring role on Millennium. His first film role was in a 1986 Andy Jones film called The Adventure of Faustus Bidgood, which features the entire cast of CODCO. Downey has enjoyed a long professional relationship with Lexx creator Paul Donovan, dating back at least to 1988, when Donovan cast Downey in the time travel adventure film, Norman's Awesome Experience. Downey will appear as Cardinal Juan de Mella in Donovan's upcoming medieval TV thriller, The Conclave.

Downey typically portrays villains, cowards, and other less-than-sympathetic types, and while he mostly appears in comic performances he has also done dramatic work. He is known for his slight Newfoundlander accent (he pronounces "the" as "da", for instance, something he carried over to the role of Stanley Tweedle).

Not long after Lexx ended its run, Downey was mugged and brutally beaten at an ATM. On his website, he has written about the prolonged and difficult recovery following this incident, a recovery that kept him from acting for some time. He appears to have made a complete recovery, and is now acting again.

Downey is also a musician and writer. Not long after Lexx ended its run it was announced he would be writing some stories for a Lexx comic book, although this project is currently in limbo. There was also talk of a Lexx spinoff TV series, although this project apparently fell through.