Julie Anne Smith (born December 3, 1960), known professionally as Julianne Moore, is an American actress. Prolific in film since the early 1990s, she is known for her portrayals of emotionally troubled women in independent films, and for her roles in blockbusters. She is the recipient of numerous accolades, including an Academy Award, a British Academy Film Award, two Golden Globe Awards, and two Emmy Awards. In 2015, Time named her one of the 100 most influential people in the world, and in 2020, The New York Times named her one of the greatest actors of the 21st century.

After studying theatre at Boston University, Moore began acting in television. From 1985 to 1988, she was a regular in the soap opera As the World Turns, earning a Daytime Emmy Award. Moore made her breakthrough with Robert Altman's ensemble film Short Cuts (1993), followed by a critically acclaimed performance in Todd Haynes' Safe (1995). Starring roles in the blockbusters Nine Months (1995) and The Lost World: Jurassic Park (1997) established her as a Hollywood leading lady. She received Oscar nominations for her roles in the period films Boogie Nights (1997), The End of the Affair (1999), Far from Heaven (2002) and The Hours (2002); in the first of these, she played a 1970s pornographic actress, while in the other three, she starred as a mid-20th century unhappy housewife.

Moore's career progressed with roles in The Big Lebowski (1998), Magnolia (1999), Hannibal (2001), Children of Men (2006), A Single Man (2009), The Kids Are All Right (2010), Crazy, Stupid, Love (2011), and Maps to the Stars (2014). She won a Primetime Emmy Award for her portrayal of Sarah Palin in the HBO film Game Change (2012), and the Academy Award for Best Actress for her portrayal of an Alzheimer's patient in Still Alice (2014). Her highest-grossing releases came with the final two films in The Hunger Games film series (2014–2015) and the spy film Kingsman: The Golden Circle (2017). She has since starred in independent films and streaming projects, including Haynes' drama May December (2023).

In addition to her acting work, Moore has written a series of children's books about a character named Freckleface Strawberry. She is married to director Bart Freundlich, with whom she has two children.