- The O'Donnell's -- The Officers
- The Official Dunzi & C-Low Swing the Selector -- The Ogyatanaa Show Band
- The Ogyatanaa Show Band -- The O'Kays
- The O'kaysions -- The Old Fashioned Revival Hour Quartet
- The Old Fourth -- The Old School Preachers
- The Old School Returns -- The Olive Group
- The Oliver Lake String Project -- The O>matics
- The Omega Baptist Church Choir -- The One
- The One -- The O'Neill Brothers
- The Oneness -- The Only Sons
- The Onlymen -- The Oozing Goo
- The Oozing Grooves -- The Opious Project
- The Opossums -- The Opposed