Thumbsucker is a 2005 American independent comedy-drama film written and directed by Mike Mills in his feature directorial debut. The film stars Lou Taylor Pucci, Tilda Swinton, Vincent D'Onofrio, Kelli Garner, Benjamin Bratt, Vince Vaughn, and Keanu Reeves. The plot focuses on Justin Cobb, a teenager in suburban Oregon, as he copes with his thumb-sucking problem, romance, and his diagnosis with ADHD and subsequent experience using Ritalin. The screenplay was adapted from the 1999 Walter Kirn novel of the same name. Swinton also served as an executive producer.

Lou Taylor Pucci is an American actor who first appeared on film in Rebecca Miller's Personal Velocity: Three Portraits in 2002. Pucci had his breakthrough leading role in Thumbsucker (2005), for which he won a Special Jury Prize at the Sundance Film Festival and the Silver Bear for Best Actor at the Berlin Film Festival. Pucci then starred in The Chumscrubber (2005), Fast Food Nation (2006), The Go-Getter (2007), Explicit Ills (2008), and Carriers (2009). Pucci had starring roles in the 2013 Evil Dead remake, as well as The Story of Luke (2013) and Spring (2014).