- Irving, David John Cawdell2
- Kaczyński, Jarosław2
- Kafka, Franz2
- Kautsky, Karl2
- Kerensky, Aleksandr Fyodorovich2
- Khaustov, Viktor Aleksandrovich2
- Kim, Il-sŏng2
- Kohn, Hans2
- Kolbe, Maximilian2
- Kostov, Vladimir2
- Krafft, Karl E.2
- Krasiński, Zygmunt2
- Kropotkin, Petr Alekseevich2
- Kuhn, Isobel2
- Kushev, Evgenii2
- Károlyi, Mihály2
- Lanz-Liebenfels, Jörg2
- Le Carré, John2
- Lenin, Vladimir Ilʹich,2
- Levi, Primo2