Rollo Armstrong (born 1967 in London ) is one half of the music producers/remixers team Rollo and Sister Bliss, and is older brother to Dido, with whom he helped to write and produce the multi-million selling albums No Angel and Life For Rent. He is also a member of the electronic music group Faithless, which he formed in 1995 with Sister Bliss, Jamie Catto and Maxi Jazz. In the United States, Rollo is best known for his production work on Dido's albums as well as singer/songwriter Kristine W's debut album, Land of the Living.

He studied at the University of York and was an active member of the student radio station, URY.

He has many musical accomplishments both within groups and solo, using various monikers: Faithless, Rollo Goes ..., Felix, Our Tribe (with Rob Dougan), and Dusted.

In 1991, Rollo founded Cheeky Records and released two records before it folded a year later because of his lack of business knowledge. Champion Records then stepped in to help with funding and advice enabling Cheeky to re-launch in 1994 (it has since been bought out by BMG). In 1992 a single was issued, named "Don't You Want Me?" (not to be confused with the 1981 song with the same name by Human League), played in heavy rotation by club DJs around the world, soon becoming a reliable floor filler. The video for the track had a fairly psychedelic feel; it consisted solely of animated graphics whose "pulsating" movement was perfectly synchronized to the beat, which made it resemble a scene demo on the classic home computers. At that time, no one had any idea about the man hiding behind the Felix handle. It was not until several months later that it was revealed that it was Rollo who had produced this track. Later in 2006, in a BBC Radio 1 interview with Pete Tong, Rollo revealed that he was paid only 300 pounds to do the track. Rollo also co-wrote the song "Who Are You?" by Australian musician Katie Noonan, appearing on her album Skin.