Alex Kingston (born 11 March 1963) is an English actress. Active from the early 1980s, Kingston became noted for her television work in both Britain and the US in the 1990s, including her regular role as Dr. Elizabeth Corday in the NBC medical drama ER (1997–2004) and her title role in the ITV miniseries The Fortunes and Misfortunes of Moll Flanders (1996), which earned her a BAFTA nomination for Best Actress.

Kingston's later credits include the recurring role of River Song in the BBC science fiction series Doctor Who (2008–2015), Mrs. Bennet in the ITV period-drama fantasy Lost in Austen (2008), Dinah Lance in The CW's superhero fiction drama series Arrow (2013–2016), and Sarah Bishop in A Discovery of Witches (2018–2022).