Saoirse-Monica Jackson is a Northern Irish actress. From 2018 to 2022 she played Erin Quinn in the Irish Channel 4 sitcom Derry Girls, as well as Cheryl Crawford in the Liverpool gangster series This City Is Ours (2025) on BBC.

Jackson was born in Derry, Northern Ireland, on 24 November 1993. As a child she divided her time between Derry and Greencastle in County Donegal, where her parents ran a village pub. After completing her GCSEs and A-Levels at St Cecilia's College in Derry, she trained in acting at the Arden School of Theatre in Manchester.

Jackson's television debut came in 2016, when she was cast as Sasha in Harlan Coben's series The Five, appearing in four episodes. In 2016 she also played Curley's wife in the Birmingham Repertory Theatre's touring production of John Steinbeck's Of Mice and Men. She made a brief appearance in the final episode of the BBC One drama series Broken (2017). In 2018 she played Shena Carney in the West End production of The Ferryman at the Gielgud Theatre.

Jackson debuted as Erin Quinn in the Channel 4 sitcom Derry Girls in the show's first episode, which aired on Channel 4 on 4 January 2018. For this role she was nominated for an IFTA Gala Television Award in the Best Female Performance category. She played the role for three seasons, until the series ended in May 2022.