Red Vienna (German: Rotes Wien) was the colloquial name for the capital of Austria between 1918 and 1934, when the Social Democratic Workers' Party of Austria (SDAP) maintained almost unilateral political control over Vienna and, for a short time, Austria as a whole. During this time, the SDAP pursued a rigorous program of construction projects across the city in response to severe housing shortages and implemented policies to improve public education, healthcare, and sanitation.

Ultimately, the collapse of the First Austrian Republic in 1934 after the suspension of the Nationalrat by Bundeskanzler Engelbert Dollfuß a year earlier and the subsequent banning of the SDAP in Austria ended the period of the first socialist project in Vienna until after the Second World War. Many of the housing complexes, or Gemeindebauten, that were built during the period continue to survive today.