- Jēgers, Benjamin̦š1
- Kassof, Allen1
- Kautsky, John H.1
- Kheifets, Aleksandr Naumovich1
- Kidron, Michael1
- Király, Béla1
- Kos-Rabcewicz-Zubkowski, Ludwik1
- Kołakowski, Leszek1
- Krakov, Stanislav1
- Krassó, György1
- Kuznetsov, B. M.1
- Lazarsfeld, Paul F.1
- Leiden, Carl1
- Leiser, Erwin1
- Levitzky, Sergei A.1
- Lipski, Józef1
- Liu, Shaoqi1
- Lombardo-Radice, Lucio1
- Longo, Luigi1
- Lunacharsky, Anatoly Vasilievich1