The aftermath of World War I saw far-reaching and wide-ranging cultural, economic, and social change across Europe, Asia, Africa, and even in areas outside those that were directly involved. Four empires collapsed due to the war, old countries were abolished, new ones were formed, boundaries were redrawn, international organizations were established, and many new and old ideologies took a firm hold in people's minds. World War I also had the effect of bringing political transformation to most of the principal parties involved in the conflict, transforming them into electoral democracies by bringing near-universal suffrage for the first time in history, as in Germany, Great Britain, and Turkey.

Following their defeat in World War I, the Central Powers agreed to pay war reparations to the Allied Powers. Each defeated power was required to make payments in either cash or kind. Because of the financial situation in Austria, Hungary, and Turkey after the war, few to no reparations were paid and the requirements for reparations were cancelled. Bulgaria, having paid only a fraction of what was required, saw its reparation figure reduced and then cancelled. Historians have recognized the German requirement to pay reparations as the "chief battleground of the post-war era" and "the focus of the power struggle between France and Germany over whether the Versailles Treaty was to be enforced or revised."