Siobhan Margaret Finneran is an English television and film actress. She made her screen debut in the 1987 independent film Rita, Sue and Bob Too, and subsequently worked consistently in television drama including roles in Coronation Street (1989–1990), Clocking Off (2000–2002) and The Amazing Mrs Pritchard (2006). In 2005, Finneran originated the lead female role in the stage play On the Shore of the Wide World and was awarded the Manchester Evening News Theatre Award for Best Actress in a Leading Role. Also a comedy performer, Finneran appeared as Janice Garvey, a leading character in the first seven series of ITV sitcom Benidorm (2007–2015). Later television roles include portraying a lawyer in the mini-series Unforgiven (2009), an embittered servant in the first three series of the costume drama Downton Abbey (2010–2012) and a recovering addict in Happy Valley (2014–2023), for which she was nominated for the 2017 British Academy Television Award for Best Supporting Actress. Later film credits include Mrs Swift in the 2013 film release The Selfish Giant, which earned her a British Independent Film Award nomination. Finneran is also a prolific television documentary narrator.

Finneran was born in Oldham, Greater Manchester, then in Lancashire, to Irish parents. She moved with her family to Saddleworth as a young child, and has lived in the area ever since. During childhood Finneran was always drawn to the performing arts and was a fan of the celebrated English comedian Eric Morecambe, recalling that "as a little girl I wanted to be Eric Morecambe. Not to be like him but to actually be him". She completed a theatre studies course.

In 2023, Finneran became patron for Manchester based charity Contact Hostel, an organisation that provides support and accommodation for teenage girls facing homelessness.