Kathryn Newton (born February 8, 1997) is an American actress. She is known for her starring roles as Louise Brooks in the CBS comedy series Gary Unmarried (2008–2010), Abigail Carlson in the HBO mystery drama series Big Little Lies (2017–2019), and Allie Pressman in the Netflix teen drama series The Society (2019). She is also known for portraying the older versions of Claire Novak in The CW dark fantasy series Supernatural (2014–2018) and Joanie Clark in the AMC period drama series Halt and Catch Fire (2016–2017).

Newton has starred in the comedy film Bad Teacher (2011), the supernatural horror film Paranormal Activity 4 (2012), for which she received the Young Artist Award for Best Leading Young Actress in a Feature Film, the crime drama film Three Billboards Outside Ebbing, Missouri (2017), the sex comedy film Blockers (2018), the drama film Ben Is Back (2018), the film Pokémon Detective Pikachu (2019), the slasher comedy film Freaky (2020), and the Amazon Studios science fiction romantic comedy-drama The Map of Tiny Perfect Things (2021).