Kristian Ayre (born November 19, 1977) is a Canadian actor perhaps best known for his portrayal of Radu from the children's science fiction show Space Cases. He has starred in a variety of films in the 1990s, namely Andre (1994), Bye Bye Birdie, a Stargate SG1 episode The Light , a 1995 TV movie, as well as The New Ghostwriter Mysteries (1997) and Nothing Too Good for a Cowboy (1998). He received his Bachelor of Fine Arts from Simon Fraser University, where he was involved in productions of Laurier (2004), Orestes (2003), Cats and Dogs (2002), and one Black Box season. His anime roles include Ryura from InuYasha the Movie: Fire on the Mystic Island, Coud Van Giruet from Elemental Gelade, Shinichiro Isumi from Hikaru no Go, and Yuji Sakai from Shakugan no Shana.

He is a founding member of the Genus Theatre.

Born in Bolton, Lancanshire, England, UK. Moved to Canada at the age of three. Kristian has two brothers, Liam and Scott. His first American role was in Andre (1994) playing Gerald. Other notable roles include Harvey Johnson in Bye Bye Birdie (1995) (TV), Strick in "New Ghostwriter Mysteries, The" (1997) and Tommy in "Nothing Too Good for a Cowboy" (1998), a Canadian series. One of his most notable roles is Radu in "Space Cases" (1996).