The Bundestag (German pronunciation: [ˈbʊndəstaːk] (listen), "Federal Diet") is the German federal parliament. It is the only federal representative body that is directly elected by the German people. It is comparable to the United States House of Representatives or the House of Commons of the United Kingdom. The Bundestag was established by Title III of the Basic Law for the Federal Republic of Germany (German: Grundgesetz, pronounced [ˈɡʁʊntɡəˌzɛt͡s] (listen)) in 1949 as one of the legislative bodies of Germany and thus it is the historical successor to the earlier Reichstag.

The members of the Bundestag are representatives of the German people as a whole, are not bound by any orders or instructions and are only accountable to their electorate. The minimum legal number of members of the Bundestag (German: Mitglieder des Bundestages) is 598; however, due to the system of overhang and leveling seats the current 20th Bundestag has a total of 736 members, making it the largest Bundestag to date and the largest freely elected national parliamentary chamber in the world.

The Bundestag is elected every four years by German citizens aged 18 or over. Elections use a mixed-member proportional representation system which combines first-past-the-post elected seats with a proportional party list to ensure its composition mirrors the national popular vote. An early election is only possible in the cases outlined in Articles 63 and 68 of the Grundgesetz.

The Bundestag has several functions. It is the chief legislative body on the federal level. The individual states (Bundesländer) of Germany participate in legislative process through the Bundesrat, a separate assembly. The Bundestag also elects and oversees the chancellor, Germany's head of government, and sets the government budget.

Since 1999, it has met in the Reichstag building in Berlin. The Bundestag also operates in multiple new government buildings in Berlin and has its own police force (the Bundestagspolizei). The current president of the Bundestag since 2021 is Bärbel Bas of the SPD. The 20th Bundestag has five vice presidents and is the most visited parliament in the world.

The Congress-Bundestag Youth Exchange (CBYX, German name: Parlamentarisches Patenschafts-Programm or PPP) is a youth student exchange program founded in 1983. The program, which is jointly sponsored by the United States Congress and the German Bundestag, funds exchange programs for German and American students through grants to private exchange organizations in both countries.

Under Germany's mixed member proportional system of election, the Bundestag has 299 constituencies (, electoral districts), each of which elects one member of the Bundestag by first-past-the-post voting (a plurality of votes). At least 299 more representatives are elected from closed lists in each of Germany's sixteen Länder, distributed in a manner that ensures that the overall proportion of representatives for each party is approximately equal to the proportion of votes its list received.