Atticus Matthew Cowper Ross (born 16 January 1968) is an English musician, record producer, composer, and audio engineer. Along with Trent Reznor, he won the Academy Award for Best Original Score for The Social Network in 2010. In 2013, the pair won a Grammy Award for Best Score Soundtrack for Visual Media for their soundtrack to The Girl with the Dragon Tattoo. In 2021, alongside Jon Batiste, they won the Golden Globe and Academy Award for the soundtrack for Pixar's Soul.

Ross began working with Reznor on the latter's side project Tapeworm in 2002. He later worked with Reznor's band Nine Inch Nails, first as a programmer and producer in 2005, and became the only official member of the band outside of Reznor in 2016. Ross was inducted into the Rock and Roll Hall of Fame as a member of Nine Inch Nails in 2020.