The Federal Assembly of Austria or Österreichische Bundesversammlung is a federal-level deliberative body consisting of the members of the two houses of the Austrian parliament, the National Council and the Federal Council, in joint session. The President of the National Council and the President of the Federal Council take turns presiding over Federal Assembly sessions. Even though it consists of the members of the legislature, the National Assembly as such is not a legislative body - the two chambers of parliament enact law and even amend the Constitution operating strictly as separate entities.

The National Assembly convenes mainly when a President needs to be sworn in, the ceremonial act of swearing in presidents being its principal responsibility. In theory, the Federal Assembly also functions as an instrument of checks and balances: upon request by a two-thirds majority of the National Council, the Federal Assembly may impeach the president before the Constitutional Court or call for a referendum to have the President removed from office by the electorate. Neither of these powers, however, has so far been exercised. The assent of the National Assembly would also be required for the President's immunity against criminal prosecution to be abrogated or for the Republic of Austria to declare war.