| Olga Lowina / Die Tiroler Holzhacker Buab'n | 1 | |
| Olga María | 3 | 1978 - 1981 |
| Olga Parhomenko | 2 | 1958 |
| Olga Rajecka-Migliniece | 1 | 1991 |
| Olga Voronets | 1 | |
| Olimpia Panciu | 1 | 1985 |
| Olin Downes | 1 | 1954 |
| The Olinger Male Quartet | 1 | |
| The Olinger Quartet | 1 | |
| Oliva Gessi | 1 | 1977 |
| Olive Walke's La Petite Musicale | 2 | 1963 |
| Oliver | 7 | 1969 - 1975 |
| Oliver And The Twisters | 1 | 1961 |
| Oliver Cheatham | 1 | 1983 |
| Oliver Cherer | 1 | 2017 |
| Oliver Dragojević | 22 | 1975 - 2022 |
| Oliver Dragojević I Zvjezdice | 1 | 1987 |
| Oliver Dragojević, Stjepan Hauser | 1 | 2021 |
| Oliver Frank | 1 | 1988 |
| Oliver I Gibonni | 1 | 2021 |
| Oliver Lake | 1 | 1982 |
| Oliver Mandić | 5 | 1981 - 1992 |
| Oliver Nelson | 5 | 1968 - 2016 |
| Oliver Nelson And The "Berlin Dreamband" | 1 | 1971 |
| Oliver Nelson Orchestra | 1 | 1962 |
| Oliver Nelson, Jimmy Forrest, King Curtis | 1 | 1988 |
| Oliver Onions | 1 | 1977 |
| Oliver Onions, M. And G. Orchestra | 1 | 1976 |
| Oliver Sain | 2 | 1972 - 1983 |
| Oliver [Yugoslavia] | 1 | 1979 |
| Los Oliver's | 1 | 1969 |
| Olivera Katarina | 8 | 1974 - 1984 |
| Olivera Marković | 2 | 1971 - 1972 |
| Olivia And David | 1 | 1977 |
| Olivia Branch Walker | 2 | 1986 |
| Olivia Jean | 3 | 2014 - 2023 |
| Olivia Molina | 3 | 1973 - 1980 |
| Olivia Newton-John | 135 | 1971 - 1989 |
| Olivia Rodrigo | 1 | 2021 |
| Olivia Ruiz | 1 | 2009 |
| Olivier Guimond | 1 | 1972 |
| Olivier Messiaen | 1 | 1957 |
| Olle Adolphson, Lars Forsell, Alf Hambe | 1 | 1971 |
| Olle Erixons | 4 | 1978 - 1983 |
| Olle Widestrand | 1 | 1968 |
| Olli Ahvenlahti | 3 | 2014 - 2024 |
| Olli Hämeen Kvintetti | 1 | 1957 |
| Ollie And The Nightingales | 1 | 1969 |
| Ollie Strong And Kenny Hepburn | 1 | 1960 |
| Ollie Van Wyk | 1 | |
| Ólöf Arnalds | 1 | 2012 |
| Olof Thunberg | 1 | 1973 |
| Olsen | 3 | 1972 - 1978 |
| Olsen And Olsen | 1 | 1987 |
| Oluma | 1 | 2024 |
| Olympians | 3 | 1970 - 1977 |
| The Olympians Scottish Dance Band | 2 | 1975 - 1983 |
| Olympic | 17 | 1969 - 1988 |
| The Olympic Bouzouki Group | 1 | 1970 |
| Olympic Runners | 9 | 1974 - 1979 |
| Olympic Sideburns | 1 | 1987 |
| The Olympic Sideburns | 1 | 1985 |
| Olympic Union And The Athenians | 1 | 1978 |
| The Olympics [D] | 1 | 1975 |
| The Olympics | 8 | 1960 - 1984 |
| Om Kalsoum : أم كلثوم | 4 | 1968 - 2018 |
| Omaha Sheriff | 1 | 1977 |
| Omar | 1 | 1991 |
| Omar And The Howlers | 9 | 1980 - 1990 |
| Omar Blondahl | 2 | |
| Omar Blondahl (Sagebrush Sam) | 1 | |
| Omar Chandler | 1 | 1991 |
| Ómar Óskarsson | 1 | 1974 |
| OMD | 1 | |
| Omega [Hungary] | 28 | 1968 - 1984 |
| The Omega Orchestra, Heinz Sandauer | 1 | 1958 |
| Omega Tribe | 2 | 1983 - 2018 |
| Omega [Australia] | 1 | |
| Omen | 2 | 1984 - 1988 |
| Omer Pobrić | 1 | 1981 |
| Omer Popaja | 1 | 1984 |
| Omni Of Halos | 1 | 2022 |
| Omni Trio | 1 | 1995 |
| Omnibus | 1 | |
| Omo The Hobo | 1 | 1967 |
| Omsk Russian Folk Choir [Государственный Омский Русский Народный Хор] | 1 | 1969 |
| On Parole [Sweden] | 1 | 2006 |
| On The Seventh Day | 1 | 1970 |
| Onaje | 1 | 1981 |
| Once More | 1 | 1980 |
| Once Upon A Time | 1 | 1990 |
| The Once Upon A Time Players | 1 | |
| Oncle Pierre, Midas | 1 | 1968 |
| Ondekoza | 1 | 1984 |
| One | 1 | 1989 |
| One + One | 1 | 1979 |
| One 2 Many | 1 | 1988 |
| One Direction | 1 | 2014 |
| One Eyed Jack | 1 | |
| One Horse Blue | 3 | 1978 - 1980 |
| One Hundred Faces | 1 | 1986 |
| One Million Fuzz-Tone Guitars | 1 | 1983 |
| One O'Clock Humph | 1 | 1992 |
| One O'Clock Gang | 1 | 1985 |
| One Plus Two | 1 | 1985 |
| One To One | 3 | 1985 - 1988 |
| One Two [Denmark] | 2 | 1986 - 1989 |
| One Two [Netherlands] | 1 | 1984 |
| One Way | 11 | 1979 - 1986 |
| One Way Featuring Al Hudson | 1 | 1980 |
| One Way System | 2 | 1983 |
| One Way Trio | 1 | |
| One [Grunt] | 1 | 1972 |
| One [UK] | 1 | 1969 |
| Onésime Grosbois Et Son Piano D'Occasion | 3 | 1960 - 1975 |
| Onésime Grosbois, Emil Stern, Luis Tuebols, Marcel Bianchi | 1 | 1958 |
| Onie Wheeler | 2 | 1982 |
| Only Child | 2 | 1988 |
| The Only Ones | 9 | 1978 - 1989 |
| Onni Gideon | 2 | 1957 - 1989 |
| Onslaught | 2 | 1987 - 1989 |
| Onur Özer | 1 | 2007 |
| Onyx And Wildwood | 1 | 1981 |
| Ooberman | 1 | 1999 |
| Oom Anneries, Grieta, Oom Fasie, Klaas, Frans, Tant Lissie, Tant Betta, Tant Annie En Dawie | 1 | 1981 |
| Oom Boet Steyn En Sy Seuns | 1 | 1986 |
| Oom Gertjie Claassen | 1 | |
| Oom Gertjie Claassen En Oom Hendrik Lotter | 1 | |
| Oom Hennie Vorster | 2 | 1966 |
| Oom Hennie Vorster Speel Sy Traporrel Met Kotie Geeringh En Sy Orkes | 1 | 1966 |
| Oom Jannie Vorster | 1 | 1978 |
| Oom Kerrie Bornman | 2 | 1978 |
| Oom Kerrie Bornman En Regardo Bornman | 1 | 1978 |
| Oom Nelie Van Rensburg | 1 | 1967 |
| Oom Sakkie | 1 | 1975 |
| Die Oorspronklike Vos Broers | 1 | |
| Die Oosrandse Jeugkoor Onder Leiding Van Sonja Van Der Walt | 4 | 1980 - 1986 |
| Oost-West Percussie Groep | 1 | 1981 |
| Opal | 4 | 1987 - 1989 |
| Opatijski Suveniri | 4 | 1976 - 1992 |
| The Open Brode | 1 | 1971 |
| The Open Mind | 2 | 1969 |
| Open Road | 1 | 1971 |
| The Open Window | 2 | 1969 |
| Operetten Ensembles Aus Wien, Hamburg Und Zürich | 1 | |
| Opeth | 4 | 2012 - 2019 |
| Ophir State Marching Band | 1 | |
| Ophiuchus | 1 | 1989 |
| Oplala | 1 | 1987 |
| OPO | 2 | 1975 - 1977 |
| Opposite Sex | 1 | 2011 |
| Opposition | 4 | 1983 - 1985 |
| The Oppressed | 2 | 1985 - 1997 |
| Optical | 1 | 1998 |
| Optimum Wound Profile | 2 | 1992 - 1993 |
| Opus | 9 | 1981 - 1986 |
| Opus 4 [Yugoslavia] | 1 | 1981 |
| Opus Alfa | 1 | 2001 |
| Opus Avantra | 1 | 1988 |
| Opus De Jazz | 1 | |
| Opus [Yugoslavia] | 2 | 1975 - 2024 |
| Ora | 2 | 1969 - 1970 |
| Oran "Juice" Jones | 1 | 1989 |
| Oran 'Juice' Jones | 1 | 1986 |
| Orane Demazis, Raimu, Pierre Fresnay, Charpin, Mouries | 1 | 1953 |
| Orang-Utan | 3 | 1971 - 2023 |
| Orange Bicycle | 3 | 1970 - 2010 |
| The Orange Blossom Sound | 1 | 1969 |
| Orange Colored Sky | 1 | 1968 |
| Orange Groove | 1 | 1969 |
| Orange Juice | 12 | 1982 - 2013 |
| Orange Peel | 2 | 1970 - 2003 |
| The Orange Peels | 1 | 2000 |
| Orange Pipe Band | 1 | 1968 |
| Orange Wedge | 2 | 1974 - 2009 |
| The Orange | 1 | 1986 |
| Orangemen Of Ulster | 1 | 1969 |
| Oranim Zabar And Geula Gill | 1 | 1961 |
| Oranim Zabar Israeli Troupe | 9 | 1958 - 1961 |
| Oranim Zabar Israeli Troupe Featuring Geula Gill | 2 | 1958 |
| Oranim Zabar Troupe Featuring Geula Gill | 3 | 1960 |
| Oratorium | 1 | 1972 |
| Orazio Frugoni | 1 | 1954 |
| Orazio Frugoni, Pro Musica Orkest, Wenen, Harold Byrns | 1 | |
| The Orb And David Gilmour | 1 | 2023 |
| The Orb | 7 | 1992 - 2024 |
| Orbis | 1 | 1980 |
| Orchester Alfred Hause | 1 | 1988 |
| Orchester Ambros Seelos | 1 | 1967 |
| Orchester Anthony Ventura | 7 | 1975 - 1979 |
| Orchester Bela Sanders | 5 | |
| Orchester Bert Landers | 2 | 1965 - 1966 |
| Orchester Billy Vaughn | 1 | 1981 |
| Orchester Bob Stiltman | 1 | 1976 |
| Orchester Bruno Bertone | 1 | |
| Orchester Burt Jackson | 2 | |
| Orchester Claudius Alzner | 2 | 1972 |
| Orchester Cliff Carpenter | 1 | |
| Orchester Des Bayerischen Rundfunks, Carl Michalski | 1 | |
| Orchester Der Bayreuther Festspiele / Karl Böhm | 1 | 1966 |