| Oehrli, Jennifer | Zuchwil (SUI) / Switzerland WOCO |  Suiza | Portero |
| O'Farrelly, Sinead | Republic of Ireland WU19 |  República de Irlanda | Defensa |
| Oferil, Marc | Andorra FUT |  Andorra | Defensa |
| Offenbacher, Daniel | Wiener Neustadt (AUT) |  Austria | Centrocampista |
| Ofori-Appiah, Willem | Genk (BEL) |  Bélgica | Defensa |
| Ogbiagbevha, Emueje | BIIK (KAZ) |  Nigeria | Delantero |
| Ogbonna, Angelo | Torino (ITA) / Italy |  Italia | Defensa |
| Oggesen, Andreas | Denmark U19 |  Dinamarca | Centrocampista |
| Oghinciuc, Costin | Gloria Bistriţa (ROU) |  Rumanía | Portero |
| Ogilvie, Connor | England U17 |  Inglaterra | Defensa |
| Ogimi, Yuki | Potsdam (GER) |  Japón | Delantero |
| Ogleby, Robert | Wrexham (WAL) / Wales U21 |  Gales | Delantero |
| O'Gorman, Aine | Peamount (IRL) / Republic of Ireland WOCO | República de Irlanda | Delantero |
| Ogu, John | Académica (POR) | Nigeria | Centrocampista |
| Ogunjimi, Marvin | Beerschot (BEL) | Bélgica | Delantero |
| Oguz Daglaroglu | Akhisar (TUR) |  Turquía | Portero |
| O'Hagan, Catherine | Glentoran (NIR) / Northern Ireland WOCO |  Irlanda del Norte | Delantero |
| Öhagen, Hjalmar | Gefle (SWE) |  Suecia | Centrocampista |
| O'Halloran, Michael | Scotland U21 |  Escocia | Delantero |
| O'Halloran, Dean | Republic of Ireland U17 | República de Irlanda | Centrocampista |
| Ohana, Daniel | Israel WU19 |  Israel | Portero |
| O'Hanlon, Ben | England U17 | Inglaterra | Defensa |
| Ohanyan, Albert | Armenia U21 |  Armenia | Portero |
| O'Hara, Mark | Scotland U19 | Escocia | Defensa |
| Ohayon, Matan | Charleroi (BEL) | Israel | Centrocampista |
| Ohi Kwoeme | Lillestrøm (NOR) / Norway U19 |  Noruega | Centrocampista |
| Ohlsson, Maja | Sweden WU19 | Suecia | Portero |
| Ohlsson, Nellie | Sweden WU17 | Suecia | Defensa |
| Öhman, Ludvig | Kalmar (SWE) / Sweden U21 | Suecia | Defensa |
| Ohno, Shinobu | Lyon (FRA) | Japón | Delantero |
| Öhrström, Stéphanie | Verona (ITA) | Suecia | Portero |
| Oier | Osasuna (ESP) |  España | Defensa |
| Oier Olazábal | Barcelona (ESP) | España | Portero |
| Õigus, Eneli | Estonia WU19 |  Estonia | Defensa |
| Oikarinen, Velma | PK-35 (FIN) |  Finlandia | Portero |
| Oikonomou, Vangelis | Ross County (SCO) |  Grecia | Defensa |
| Oikonomou, Kostas | Greece U17 | Grecia | Defensa |
| Õisma, Kairi | Estonia WU17 | Estonia | Defensa |
| Ojala, Mika | Häcken (SWE) / Finland | Finlandia | Centrocampista |
| Ojala, Juhani | Terek (RUS) / Finland | Finlandia | Defensa |
| Ojala, Grete | Pärnu (EST) / Estonia WOCO | Estonia | Defensa |
| Ojala, Matias | Finland U19 | Finlandia | Centrocampista |
| Ojamaa, Henrik | Motherwell (SCO) / Estonia | Estonia | Delantero |
| Ojanperä, Juha | Ilves (FIN) / Finland FUT | Finlandia | Portero |
| Ojanperä, Rami | Finland U17 | Finlandia | Centrocampista |
| Ojanperä, Aleksi | Finland U17 | Finlandia | Defensa |
| Ojo, Funso | Beerschot (BEL) / Belgium U21 | Bélgica | Centrocampista |
| Ojo, Oluwaseyi | England U17 | Inglaterra | Centrocampista |
| Ojo, Kim | Genk (BEL) | Nigeria | Delantero |
| Okan Alkan | Kayserispor (TUR) / Turkey U21 | Turquía | Defensa |
