The States of the Weimar Republic were the first-level administrative divisions and constituent states of the German Reich during the Weimar Republic era. The states were established in 1918 following the German Revolution upon the conclusion of World War I, and based on the 22 constituent states of the German Empire that abolished their local monarchies. The new states continued as republics alongside the three pre-existing republican city-states within the new Weimar Republic, adopting the titles Freistaat ("Free State") or Volksstaat ("People's State").

Germany suffered significant territorial losses from the Treaty of Versailles following World War I, and some states had their borders altered by international border changes. In 1920, the state of Thuringia was formed from the former Ernestine duchies that continued briefly as republics before merging, except for Saxe-Coburg, which became part of Bavaria. Additionally, the Saar Basin and the city of Danzig were detached from Germany and placed under the administration of the League of Nations.

The states of the Weimar Republic were effectively abolished after the establishment of Nazi Germany in 1933 by a series of laws and decrees between 1933 and 1935, and autonomy was replaced by direct rule of the National Socialist German Workers' Party in the Gleichschaltung process. The states continued to formally exist as de jure bodies, but from 1934 were superseded by de facto Nazi Party administrative units called Gaue. Many of the states were formally dissolved at the end of World War II by the Allies, and ultimately re-organised into the modern states of Germany.

In July 1932, the government of Prussia, by far the largest of the German states, had already been taken over by the Reich in the Preußenschlag under then Reich Chancellor Franz von Papen. Following the Nazi seizure of power, they sought to gain direct control over all the remaining states after winning the general election of March 1933. The independent state governments and parliaments were successively abolished, and the Reich government took over direct control in a process called Gleichschaltung ("coordination").

Barely a week after the passage of the Enabling Act of 1933, which effectively made Adolf Hitler the dictator of Germany, the Nazi government issued the Provisional Law on the Coordination of the States with the Reich (German: Vorläufiges Gesetz und Zweites Gesetz zur Gleichschaltung der Länder mit dem Reich) on 31 March 1933. This law dissolved the duly-elected sitting state parliaments of the German states except for the Prussian parliament which the Nazis already controlled. It then reconstituted them based on the electoral results of the 5 March 1933 election, except that the seats won by the Communist Party were expressly excluded. This law essentially nullified the results of the most recent state parliamentary elections and effectively installed a working majority for the Nazis in each state.

A week later, the Nazi government issued the Second Law on the Coordination of the States with the Reich (German: Zweites Gesetz zur Gleichschaltung der Länder mit dem Reich) on 7 April 1933. This law created the office of Reichsstatthalter (Reich Governor) and deployed one in each state. The Reich Governors were given the task of overseeing the fulfillment of Hitler's political guidelines in the states. Indeed, the law required them to carry out "the general policy of the Chancellor." In practice, they acted as proconsuls with complete authority over the state governments. They were empowered to dissolve the state parliaments, preside over the state government and appoint and dismiss ministers, judges and other state officials. In Prussia, Hitler himself was designated by the law as Reichstatthalter. However, he delegated his authority to Hermann Göring, whom he installed as Prussian minister president on 11 April 1933 without an election. The Prussian provinces were similarly administered by an appointed Oberpräsident, usually the local Nazi Party Gauleiter.

The Law on the Reconstruction of the Reich (German: Gesetz über den Neuaufbau des Reichs), passed on 30 January 1934, formally de-federalized the Reich for the first time in its history. However, Germany already had effectively become a highly centralized state with the passage of the Enabling Act and the posting of the Reich Governors. This law transferred the states' sovereignty to the Reich, and their parliaments were formally abolished. The Reich Governors were made responsible to the Reich Minister of the Interior, Wilhelm Frick. The Law on the Abolition of the Reichsrat (German: Gesetz über die Aufhebung des Reichsrats), issued on 14 February 1934, formally abolished the upper chamber of the Reich parliament, which represented the states in the formation of national legislation. For all intents and purposes, the states were reduced to mere administrative units of the Reich government.

The Reich Governors Law (German: Reichsstatthaltergesetz) of 30 January 1935 formally designated the Reich Governors as the representatives of the Reich government, appointed to watch over the execution of the political guidelines issued by the Führer und Reichskanzler (Hitler). They received the authority to "inform" the provincial authorities about the guidelines and the measures to fulfill them. The Reichsstatthalter were now also empowered to take over all functions of state government. They also appointed the mayors of all towns and cities with populations fewer than 100,000. This had the effect of giving the Reich Interior Ministry near-complete control over local government. The Interior Minister appointed the mayors of all cities with populations greater than 100,000 (though Hitler reserved the right to appoint the mayors of Berlin and Hamburg himself if he deemed it necessary) and, as mentioned above, the Reich Governors were responsible to him.

After World War I, the Saar Basin was occupied and governed jointly by the United Kingdom and France from 1920 to 1935 under a League of Nations mandate.^[1] After a plebiscite was held in January 1935, the region was returned to Germany.^[2]

In accordance with the Treaty of Versailles, the city of Danzig (now Gdańsk, Poland) was detached from Germany on 15 November 1920 and turned into a semi-autonomous city-state under the protection of the League of Nations.^[3][4] The Treaty stated that it was to remain separate from both Germany and the newly independent Poland, but was not its own sovereign state.^[5] After Germany invaded Poland in September 1939, the city's autonomous status was revoked and it was annexed by Germany.

• Provinces of Prussia
• States of the German Confederation
• States of the German Empire
• Administrative divisions of Nazi Germany
• Administrative divisions of East Germany
• States of Germany