Antonia Eugenia "Nia" Vardalos (born September 24, 1962) is a Canadian-American actress, screenwriter, director, and producer. Her most notable work is the 2002 film My Big Fat Greek Wedding, which garnered her nominations for the Academy Award for Best Original Screenplay, and the Golden Globe Award for Best Actress – Motion Picture Comedy or Musical. She's also known for starring in the sequel My Big Fat Greek Wedding 2, and the TV series My Big Fat Greek Life.

She starred in the films Connie and Carla, My Life in Ruins, I Hate Valentine's Day, and Helicopter Mom. She starred on TV as Domino in Team Knight Rider and as Annie Spiro in Graves. She hosted The Great American Baking Show along with her then husband, actor Ian Gómez.