Kazimierz Zakrzewski (November 4, 1900 in Kraków – March 11, 1941 in Palmiry) was a Polish historian and publicist, a professor of the University of Warsaw.

Zakrzewski was a co-originator of the Polish syndicalist movement, activist of the trade union Związek Związków Zawodowych, and researcher of ancient history (mainly late-ancient) and the Byzantine culture.

He wrote Historia Bizancjum ("History of the Byzantine Empire") and co-authored the Polish popular history encyclopedia Wielka historia powszechna.

During World War II, Zakrzewski was murdered by the Germans in a mass execution at Palmiry.

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