Katherine Kelly is an English actress. She rose to prominence with her portrayal of Becky McDonald on the ITV soap opera Coronation Street (2006–2012), for which she received multiple awards, including the British Soap Award for Best Actress (2009) and the NTA for Best Serial Drama Performance (2012).

Kelly's subsequent television roles include Lady Mae in Mr Selfridge (2013–2014, 2016), DI Jodie Shackleton in Happy Valley (2016), Miss Andrea Quill in Class (2016), Jane Lowry in Strike Back (2017–2018), DCI Natalie Hobbs in Criminal: UK (2019–2020), Elizabeth Sutherland in Gentleman Jack (2019–2022), DI Karen Renton in Liar (2020), Sally Wright in Innocent (2021), and Angela van Den Bogerd in Mr Bates vs The Post Office (2024).

Katherine Kelly was born in Barnsley, South Yorkshire. She grew up in both South Yorkshire and the United States. She has strong links with The Lamproom Theatre in Barnsley, established in 1998 by her father John (who is originally from Castleisland, County Kerry, Ireland), and has regularly supported fund-raising events held there.

She trained at the Royal Academy of Dramatic Art with fellow students Meredith MacNeill, Leo Bill, Elliot Cowan, Laurence Fox, and actor and novelist Anna Hope, graduating in 2001.