German annexation of Austria in March 1938. Austria was annexed into the German Third Reich on 12 March 1938. There had been several years of pressure by supporters from both Austria and Germany (and both Nazis and non-Nazis) for the "Heim ins Reich" movement. Earlier, Nazi Germany had provided support for the Austrian National Socialist Party (Austrian Nazi Party) in its bid to seize power from Austria's Austrofascist leadership.