| Ouladboutaher, Faylal | Roubaix (FRA) / France FUT |  France | Forward |
| Õunap, Janar | Estonia U19 |  Estonia | Defender |
| Õunpuu, Kethy | Estonia WOCO | Estonia | Midfield |
| Ousager, Emil | AGF (DEN) |  Denmark | Goalkeeper |
| Oussalah, Mustapha | Kortrijk (BEL) |  Morocco | Midfield |
| Ousted, David | Randers (DEN) | Denmark | Goalkeeper |
| Ovadia, Roy | Tel-Aviv (ISR) / Israel FUT |  Israel | Forward |
| Ovdiychuk, Olha | Kharkiv (UKR) / Ukraine WOCO |  Ukraine | Forward |
| Overmeire, Killian | Lokeren (BEL) |  Belgium | Midfield |
| Overtoom, Willie | AZ (NED) |  Netherlands | Forward |
| Ovesen, Kim Rune | Vegakameratene (NOR) / Norway FUT |  Norway | Forward |
| Oviedo, Bryan | Everton (ENG) |  Costa Rica | Defender |
| Ovono Ebang, Didier Janvier | Sochaux (FRA) |  El Salvador | Goalkeeper |
| Øvretveit, Øystein | Brann (NOR) / Norway U19 | Norway | Goalkeeper |
| Ovseannicov, Gheorghe | Olimpia (MDA) / Moldova |  Moldova | Forward |
| Ovsyannikov, Denys | Energy (UKR) / Ukraine FUT | Ukraine | Forward |
| Ovsyannikov, Vladislav | Russia U19 |  Russia | Midfield |
| Owain Jones | Inverness (SCO) / Wales |  Wales | Midfield |
| Owen, Michael | Stoke (ENG) |  England | Forward |
| Owen, Gareth | Wales U17 | Wales | Goalkeeper |
| Owomoyela, Patrick | Dortmund (GER) |  Germany | Defender |
| Owusu, Edward | AIK (SWE) / Sweden U19 |  Sweden | Midfield |
| Owusu, Leroy | Netherlands U17 | Netherlands | Defender |
| Owusu-Abeyie, Quincy | Panathinaikos (GRE) | Netherlands | Forward |
| Oxlade-Chamberlain, Alex | Arsenal (ENG) / England / England U21 | England | Midfield |
| Oyebanjo, Olanrewaju | York (ENG) / Republic of Ireland U21 |  Republic of Ireland | |
| Ozan İpek | Mersin (TUR) |  Turkey | Midfield |
| Özay Özütok | Istanbul (TUR) / Turkey FUT | Turkey | Forward |
| Özbayraktar, Serdar | Gaziantepspor (TUR) | Turkey | |
| Özbek, Burak | Hamburg (GER) | Germany | Forward |
| Özbiliz, Aras | Kuban (RUS) / Armenia | Netherlands | Forward |
| Ožbolt, Alen | Slovenia U17 |  Slovenia | Forward |
| Özcan, Ramazan | FC Ingolstadt 04 (GER) / Austria |  Austria | Goalkeeper |
| Özçelik, Oguzhan | Horsens (DEN) | Turkey | Midfield |
| Ozdamar, Suleyman | Gaziantepspor (TUR) | Turkey | Defender |
| Ozdoev, Magomed | Lokomotiv Moskva (RUS) / Russia / Russia U21 | Russia | Midfield |
| Ožegović, Ognjen | Serbia U19 |  Serbia | Forward |
| Özek, Ahmet İlhan | Karabükspor (TUR) | Turkey | Midfield |
| Özer Hurmacı | Kasımpaşa (TUR) | Turkey | Midfield |
| Özgen, Tolga | Elazığspor (TUR) | Turkey | |
| Özgür Çek | Eskişehirspor (TUR) / Turkey U21 | Turkey | Defender |
| Özgürcan Özcan | Akhisar (TUR) | Turkey | Forward |
| Özil, Mesut | Real Madrid (ESP) / Germany | Germany | Midfield |
| Ozimo, Arianna | Italy WU19 |  Italy | Goalkeeper |
| Özkan, Gabriel | AIK (SWE) | Sweden | Midfield |
| Özkan Karabulut | Gençlerbirliği (TUR) / Turkey U21 | Turkey | Goalkeeper |
| Özkara, Cihan | Sivasspor (TUR) / Azerbaijan / Azerbaijan U21 |  Azerbaijan | Forward |
| Özmert, Hakan | Karabükspor (TUR) | Turkey | Midfield |
| Ozobić, Filip | Croatia U21 |  Croatia | Midfield |
| Ozokwo, Nduka | Mersin (TUR) |  Nigeria | Forward |
