Julianne Moore (born Julie Anne Smith; December 3, 1960) is an American actress and children's author. Prolific in film since the early 1990s, she is known for her portrayals of emotionally troubled women in independent films and her roles in blockbusters. She has received 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; in 2020, The New York Times named her one of the greatest actors of the 21st century.

After studying theatre at Boston University, she 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 an unhappy mid-20th century housewife.