Katherine Boyer Waterston (born March 3, 1980) is a British-American actress. She made her feature film debut in Michael Clayton (2007). She had supporting roles in films including Robot & Frank, Being Flynn (both 2012) and The Disappearance of Eleanor Rigby (2013), before her breakthrough performance in Inherent Vice (2014). She portrayed Chrisann Brennan in Steve Jobs (2015), and went on to star in Fantastic Beasts and Where to Find Them (2016) and its sequels. Her other film roles were in Alien: Covenant (2017), Logan Lucky (2017), The Current War (2017), Mid90s (2018) and The World to Come (2020).

Early life
Katherine Boyer Waterston was born March 3, 1980 in Westminster, London, the daughter of American parents, Lynn Louisa (née Woodruff), a former model, and actor Sam Waterston. She holds dual citizenship. Her father is of English and Scottish descent. Her sister is actress Elisabeth Waterston and her brother is director Graham Waterston. She has an older half-brother, James Waterston, also an actor.

She was raised in Connecticut, and graduated from the Loomis Chaffee School in 1998.