Atticus Matthew Cowper Ross is an English musician, composer, record producer, and audio engineer. He is best known for his work with American musician Trent Reznor, with whom he first worked on the musical project Tapeworm in 2002. He began working with Reznor's band Nine Inch Nails in 2005 as a programmer and producer, then joined as a musician and became the only official member of the band other than Reznor in 2016.
Outside of Nine Inch Nails, Ross and Reznor have become known for their work on film scores. They won the Academy Award for Best Original Score for The Social Network in 2010, the Grammy Award for Best Score Soundtrack for Visual Media for The Girl with the Dragon Tattoo in 2013, and the Golden Globe and Academy Award for Soul in 2021.
Ross was inducted into the Rock and Roll Hall of Fame as a member of Nine Inch Nails in 2020. He and Reznor co-created the virtual supergroup WitchGang in 2023.