| Cäsar Rüstow | |
| Birth Date: | 18 June 1826 |
| Birth Place: | Brandenburg an der Havel, Kingdom of Prussia |
| Death Place: | Dermbach, Kingdom of Prussia |
| Battles: | Austro-Prussian War
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Cäsar Rüstow (18 June 1826 – 4 July 1866) was a Prussian soldier and military writer.
The brother of Wilhelm Rüstow and Alexander Rüstow, Cäsar Rüstow was one of the foremost experts of his time in the design and construction of military rifles, and the writer of several treatises on that subject, notably Die Kriegshandfeuerwaffen (Berlin, 1857–64). Both Alexander and Cäsar fell on the field of battle in the war of 1866, Cäsar at the Battle of Dermbach. He was the grandfather of the sociologist Alexander Rüstow.