The Austro-Prussian War or Seven Weeks' War (in Germany also known as German War, Seven Weeks War, Unification War, German–German War, German Civil War or Fraternal War) was a war fought in 1866 between the German Confederation under the leadership of the Austrian Empire and its German allies on one side and the Kingdom of Prussia with its German allies and Italy on the other, that resulted in Prussian dominance over the German states. In the Italian unification process, this is called the Third Independence War.

The major result of the war was a shift in power among the German states away from Austrian and towards Prussian hegemony, and impetus towards the unification of all of the northern German states in a Kleindeutschland that excluded Austria. It saw the abolition of the German Confederation and its partial replacement by a North German Confederation that excluded Austria and the South German states. The war also resulted in the Italian annexation of the Austrian province of Venetia.