| Oliver Heldens x Firebeatz & Schella ft. Carla Monroe | LIft Me Up | — | 125 | — | — | 2020 |
| Olly Murs | Army Of Two | (Kat Krazy Remix) | 125 | Dance | Epic | 2012 |
| Omar Enrique ft. Ilegales | Tu | Remix | 125 | Merengue Mambo | GM | 2012 |
| Omega | Que Tengo Que Hacer | — | 125 | — | Planet | 2009 |
| Omega ft. Daddy Yankee | Que Tengo Que Hacer | (Planet) Remix | 125 | — | Planet | 2009 |
| One Bit ft. Laura White | Back To You | The Last Indigo Extended Mix | 125 | Progressive House | The Last Indigo Extended Mix | 2019 |
| One Direction | What Makes You Beautiful | — | 125 | — | Columbia | 2012 |
| One Direction | What Makes You Beautiful | Quick Edit* | 125 | — | Columbia | 2012 |
| One Direction | What Makes You Beautiful | Quick Edit | 125 | Top 40 | Columbia | 2012 |
| One Eskimo | Kandi | Cicada Vocal Club Mix | 125 | — | Shangri-La | 2011 |
|
| One World Order | They Wanna Be Free | Original Mix | 125 | — | Focus Music | 2002 |
| Onionz | Space Bass | Tim Cook Remix | 125 | — | Endemic Digital | 2009 |
| Onur Ozman | Hold On | Original Mix | 125 | — | Onethirty | 2011 |
| Openair | The Octagon | Global Jaxx Remix | 125 | — | Suesse Records | 2007 |
| Ophelie Winter | I Spy | Dance Extended Mix | 125 | — | East/west Records/elektra | 1999 |
| Opus Black | Feels Like Home | Original Club Mix | 125 | — | Transmission | 2013 |
| Opus III | It's A Fine Day | Marco's Fave Mix | 125 | — | East West Records | 1992 |
| Orgy | Opticon | Pink Noise Fashion Bomb Vocal Mix | 125 | — | Elementree/reprise Records | 2001 |
| Orlando Conga | Somo Asi | — | 125 | — | Unsigned | 2009 |
| Orquesta Tamarindos | Amor De Novela | — | 125 | Merengue Mambo | Cuaima | 2011 |
|
| Ortzroka | Bulb Fuel | Ortzroka Deep Mix | 125 | — | Verk Records | 2007 |
| Oscar De Rivera Vs. Circus Night | Mesala | Boncho Remix | 125 | Tribal | Stereo Productions | 2002 |
| Oscar G. ft. Tamara Wallace | Your Love | Jaimy Mix | 125 | — | Nervous | 2010 |
| Outkast | Spotie Ottie Dopolicious | — | 125 | Hip-Hop | — | — |
| Ovr Kill | Fassbender | Original Mix | 125 | — | Glasgow Underground | 2013 |