Emily Kathleen Anne Mortimer (born 6 October 1971) is a British actress and filmmaker. She began acting in stage productions and has since appeared in several film and television roles. In 2003, she won an Independent Spirit Award for her performance in Lovely and Amazing. She is also known for playing Mackenzie McHale in the HBO series The Newsroom (2012–2014). She co-created and co-wrote the series Doll & Em (2014–2015) and wrote and directed the miniseries The Pursuit of Love (2021), the latter of which earned her a nomination for the British Academy Television Award for Best Supporting Actress.

She provided Sophie's voice in the English-language version of Howl's Moving Castle (2004). She starred in Scream 3 (2000), Match Point (2005), The Pink Panther (2006), The Pink Panther 2 (2009), Lars and the Real Girl (2007), Chaos Theory (2008), Harry Brown (2009), Shutter Island (2010), Cars 2 (2011), Hugo (2011), Mary Poppins Returns (2018), and Relic (2020).