John Scot Barrowman (born 11 March 1967) is a Scottish-American actor, author, presenter, singer and comic book writer. He is known for his roles as Captain Jack Harkness in Doctor Who (2005–10; 2020–21) and spin-off Torchwood, (2006–11) and as Malcolm Merlyn in the Arrowverse (2012–19).

Born in Glasgow, Barrowman moved to the US state of Illinois with his family at the age of eight. Encouraged by his high school teachers there, he studied performing arts at the United States International University in San Diego before landing the role of Billy Crocker in Cole Porter's Anything Goes in London's West End. Since his debut, he has played a number of roles in various musicals both in the West End and on Broadway, including Miss Saigon, The Phantom of the Opera, Sunset Boulevard, and Matador. After appearing in Sam Mendes' production of The Fix, he was nominated for the 1998 Laurence Olivier Award for Best Actor in a Musical and, in the early 2000s, returned to the role of Billy Crocker in the revival of Anything Goes. His most recent West End credit was in the 2009 production of La Cage aux Folles.

Alongside his theatrical career, Barrowman has appeared in films such as the musical biopic De-Lovely (2004) and musical comedy The Producers (2005). Before venturing into British television, he featured in the American television dramas Titans and Central Park West, but is better known for his acting and presenting work for the BBC; this includes his work for CBBC in its earlier years, his self-produced entertainment programme Tonight's the Night, and his BAFTA Cymru-nominated role of Captain Jack Harkness in the 2005 revival of the sci-fi series Doctor Who and its spin-off Torchwood. Barrowman has also had a number of guest roles in television programmes both in the US and the UK. He appeared as a contestant on the first series of celebrity ice skating show Dancing on Ice while his theatrical background allowed him to become a judge on Andrew Lloyd Webber's musical talent shows How Do You Solve a Problem like Maria?, Any Dream Will Do and I'd Do Anything. With this experience, he joined the judging panel of Dancing on Ice for the 2020 to 2021 series. In 2006, he was voted Stonewall's Entertainer of the Year. He hosted the BBC One quiz show Pressure Pad in 2013 and 2014. Barrowman starred in The CW's Arrow and Legends of Tomorrow as Malcolm Merlyn.

Barrowman is also featured on more than 12 musical theatre recordings, including cover tunes found on his 2007 album Another Side and 2008's Music Music Music. Both albums accrued places on the UK Albums Chart, as did his self-titled John Barrowman (2010), which reached No. 11, his highest chart placing to date. He has published two memoirs and autobiographies, Anything Goes (2008) and I Am What I Am (2009), with his older sister Carole as co-author. The siblings also teamed up to write a series of young-adult fantasy novels, Hollow Earth. The second book in the series, Bone Quill, was released 2013, with the third, Book of Beasts published in 2014. A second trilogy, The Orion Chronicles, followed with Conjuror published in 2016, Nephilim in 2017, and Inquisitor in 2018.