| Karlsson, Per | AIK (SWE) |  Sweden | Defender |
| Karlsson, Maria Josefina | Verona (ITA) | Sweden | Defender |
| Karlsson, Gustav | Skövde (SWE) / Sweden FUT | Sweden | Defender |
| Karlsson, Josef | Öster (SWE) | Sweden | Midfield |
| Karlsson, Ellen | Sweden WU19 | Sweden | Defender |
| Karlsson, Jennifer | Sweden WU17 | Sweden | Forward |
| Karmazinas, Artūras | Nautara Kaunas (LTU) / Lithuania FUT |  Lithuania | Defender |
| Kärnä, Sara | PK-35 (FIN) |  Finland | Forward |
| Karner, Maximilian | Ried (AUT) / Austria U21 |  Austria | Defender |
| Karnezis, Orestis | Panathinaikos (GRE) / Greece |  Greece | Goalkeeper |
| Karofeld, Magnus | Estonia U17 |  Estonia | Goalkeeper |
| Karouni, Ryad | Issy (FRA) / France FUT |  France | Goalkeeper |
| Karpova, Nadezhda | Russia WU19 |  Russia | Forward |
| Karpovich, Sergei | Belarus U19 |  Belarus | Defender |
| Karra, Zacharoula | Greece WOCO | Greece | Forward |
| Karstoft, Ida | Denmark WU19 |  Denmark | Defender |
| Karuru, Ovidy | Leuven (BEL) |  Zimbabwe | |
| Karuykin, Bogdan | Kuban (RUS) | Russia | |
| Karyaka, Andrei | Volga (RUS) | Russia | Midfield |
| Kaş, Erkan | Beşiktaş (TUR) |  Turkey | Midfield |
| Kasaev, Alan | Rubin (RUS) | Russia | Midfield |
| Kasalica, Filip | Montenegro |  Montenegro | Forward |
| Kasami, Pajtim | Luzern (SUI) / Switzerland U21 |  Switzerland | Midfield |
| Kašćelan, Mladen | Panthrakikos (GRE) | Montenegro | Midfield |
| Kaselytė, Greta | Gintra (LTU) / Lithuania WOCO | Lithuania | Goalkeeper |
| Kashia, Guram | Vitesse (NED) / Georgia |  Georgia | Defender |
| Kaskov, Artur | Metalurh Zaporizhya (UKR) / Ukraine U21 |  Ukraine | Forward |
| Kasmeridis, Alexandros | Levadiakos (GRE) | Greece | Goalkeeper |
| Kasparov, Gevorg | Armenia |  Armenia | Goalkeeper |
| Kastlová, Gabriela | Slovan Bratislava (SVK) / Slovakia WU19 |  Slovakia | Defender |
| Kastrati, Flamur | Erzgebirge (GER) / Norway U21 |  Norway | Forward |
| Kastrati, Elhan | Albania U17 |  Albania | Goalkeeper |
| Kasyan, Olexandr | Karpaty (UKR) | Ukraine | Forward |
| Katajeva, Kristine | Latvia WOCO |  Latvia | Defender |
| Katelaris, Fanos | Cyprus U17 |  Cyprus | Midfield |
| Katevtsian, Petros | Greece FUT | Greece | Defender |
| Katidis, Giorgos | AEK (GRE) / Greece U21 | Greece | Midfield |
| Katona, Máté | Vasas (HUN) / Hungary U21 |  Hungary | Midfield |
| Katsaev, Adlan | Terek (RUS) | Russia | Midfield |
| Katsiati, Giorgos | Cyprus U17 | Cyprus | Forward |
| Katsikas, Giorgos | PAOK (GRE) / Greece U21 | Greece | Defender |
| Katsikas, Argyrios | Greece U17 | Greece | Midfield |
| Katsouranis, Kostas | PAOK (GRE) / Greece | Greece | Midfield |
| Katz, Guillaume | Lausanne (SUI) | Switzerland | Defender |
| Katzer, Markus | Rapid Wien (AUT) | Austria | Defender |
| Kauber, Kevin | Estonia U19 | Estonia | Forward |
| Kaufmann, Daniel | Vaduz (LIE) / Liechtenstein / Liechtenstein U21 |  Liechtenstein | Midfield |
| Kaufmann, Leonhard | Sturm (AUT) | Austria | Midfield |
| Kauko, Joni | Finland U21 | Finland | Midfield |
| Kauppi, Kalle | Finland U21 | Finland | Midfield |
