Mary Sweeney is an American film editor and producer best known for collaborating with the avant-garde American film director, David Lynch. Sweeney worked with Lynch on several critically acclaimed films and television series, most notably as a film editor on the cult hits Twin Peaks, Lost Highway, and Mulholland Drive for Lynch's Asymmetrical Productions company. She was the co-author, with John Roach, of The Straight Story.
Sweeney was for many years a domestic partner with David Lynch. The couple married in 2006 but filed for divorce one month later, citing irreconcilable differences. Together the couple has one son, Riley Sweeney Lynch, born in 1992.
A long-time Hollywood resident, Sweeney is head of The Sullivan Canyon Riders Club, a Los Angeles-based equestrian club. The club has worked to prevent land used by equestrians from being sold to developers, an effort that was supported financially by well-known film director Steven Spielberg and actress Kate Capshaw.