Josef "Sepp" Plieseis (20 December 1913 – 21 October 1966) was an Austrian resistance fighter against the Nazi regime.

After the defeat of the Republican forces, he fled to France where was arrested and incarcerated in concentration camps in Gurs, St. Cyprienne, und Argiles before returning to his home in Salzkammergut.

Although an SS training camp was located in the same place, bringing together 1500 to 2000 men, he managed, with the help of female agricultural workers, to flee through the mountains on October 23, 1943 and to hide in the upper Salzkammergut.

It was there that he organized a resistance group against National Socialism whose priority objective was to hide deserters from the region in the mountains.

After the war, he served in various political appointments in his home area and remained a member of the Communist Party of Austria.