Alexandra Roach (born 23 August 1987) is a Welsh actress.
A fluent Welsh speaker, Roach appeared in long-running television soap Pobol Y Cwm in her early teens and won Best Juvenile Actor in a Soap at the Children in Entertainment Awards. After leaving the show in 2005, she spent time with the National Youth Theatre of Wales before going on to the Royal Academy of Dramatic Art, graduating with a B.A. in acting in 2010. A number of high-profile roles followed, including Sasha in Being Human, Beth Partridge in Candy Cabs, and The Suspicions of Mr Whicher (in which she played notorious child murderer Constance Kent).
Roach starred as a young Margaret Thatcher in The Iron Lady. She appeared as Helene in Sky Comedy's Hunderby in autumn 2012. Roach has also been cast as Molly in the film adaptation of Michael Morpurgo's 2003 novel Private Peaceful. She was included on the Screen International "Stars of Tomorrow" list in 2011. In January 2013, she began starring in the British TV series Utopia.
On 3 June 2013, Roach appeared in the fifth episode of new ITV comedy Vicious, as Ash's vegan girlfriend Chloe. She returned to the role for one episode in June 2015. On 8 August 2014, she appeared in the inaugural episode of the BBC comedy Walter.