The Riksdag (Swedish: [ˈrɪ̌ksdɑː(ɡ)] (listen), lit. transl. "diet of the realm"; also Swedish: riksdagen [ˈrɪ̌ksdan] (listen) or Sveriges riksdag [ˈsvæ̌rjɛs ˈrɪ̌ksdɑː(ɡ)] (listen)) is the legislature and the supreme decision-making body of Sweden. Since 1971, the Riksdag has been a unicameral legislature with 349 members (riksdagsledamöter), elected proportionally and serving, since 1994, fixed four-year terms. The 2022 Swedish general election is the most recent general election.

The constitutional mandates of the Riksdag are enumerated in the Instrument of Government (Regeringsformen), and its internal workings are specified in greater detail in the Riksdag Act (Riksdagsordningen). The seat of the Riksdag is at Parliament House (Riksdagshuset), on the island of Helgeandsholmen in the central parts of Stockholm. The Riksdag has its institutional roots in the feudal Riksdag of the Estates, traditionally thought to have first assembled in Arboga in 1435. In 1866, following reforms of the 1809 Instrument of Government, that body was transformed into a bicameral legislature with an upper chamber (Första Kammaren) and a lower chamber (Andra Kammaren).