Otto Planetta (2 August 1899 in Vyškov, Austro-Hungarian Empire, now Czech Republic – 31 July 1934 in Vienna, Austria) was an Austrian Nazi. On 25 July 1934 he murdered Engelbert Dollfuss, Austrian Chancellor during the unsuccessful July Putsch, four years before the Anschluss. He and the other assassins were members of SS Regiment 89. He was sentenced to death and executed by hanging. He was cremated at Feuerhalle Simmering, his ashes are buried at Dornbacher Friedhof in Vienna.
- Assassination in Vienna, Walter B. Maass, published by Charles Scribners's Sons, New York
- The Order of the Death's Head: The Story of Hitler's SS, by Heinz Zollin Höhne and Richard Barry
- První zemřel kancléř, Vladimír Bauman a Miroslav Hladký, Praha 1968
- Na dně byla smrt, Otakar Brožek a Jiří Horský, Praha 1968