This is a list of parliamentary assemblies of Iceland. Assemblies of Parliament in Iceland correspond to parliaments in the United Kingdom and congresses in the United States. Each parliamentary assembly (Icelandic: þing) is divided into meetings. Each parliamentary meeting (Icelandic: þingfundur) typically lasts a few hours and multiple meetings can occur the same day. Parliamentary assemblies are either regular assemblies (Icelandic: regluleg þing), beginning the second Tuesday of September and lasting a year, or extra-assemblies (Icelandic: aukaþing), beginning after elections in spring and adjourning before the start of a regular assembly.

Although parliamentary assemblies are sometimes referred to as sessions in English and extra-assemblies as special sessions, they are in fact not sessions. Assemblies, which typically last no more than a full year, divide solely into meetings. The business of an assembly, i.e. its schedule of meetings, may be postponed and resumed as need be, for instance to allow for summer holidays.

• Commonwealth of Iceland (930–1262)
  • Parliament was founded at Þingvellir in 930. It held both legislative and judicial power but no executive power was present in the country.
• Union with Norway (1262–1814)
  • When Iceland became a dependency of Norway, the legislative power of Parliament was shared with the king of Norway who ruled through his officials. Laws adopted by Parliament were subject to royal assent and, conversely, if the king initiated legislation, Parliament had to give its consent.
• Danish monarchy (1380–1944)
  • Norway falls under the control the Danish monarchy and Iceland along with it. Parliament served almost exclusively as a court of law until the year 1800 when it was disbanded by royal decree.
  • A royal decree providing for the reestablishment of Parliament was issued on 8 March 1843. Elections were held the following year and the assembly finally met on 1 July 1845. Parliament functioned however only as a consultative assembly.
• Constitution of Iceland (1874)
  • The constitution of 1874 granted to Parliament joint legislative power with the crown in matters of exclusive Icelandic concern. The king retained the right to veto legislation and often, on the advice of his ministers, refused to consent to legislation adopted by Parliament.
  • Parliament began meeting in the newly built Parliament House in 1881 and has done so ever since.
  • A constitutional amendment, confirmed on 3 October 1903, granted Icelanders home rule and parliamentary government.
  • After 1915 standing committees began operating in Parliament for the first time. Parliament was bicameral and each chamber had the same seven standing committees.
• Kingdom of Iceland (1918–1944)
  • Parliament was granted unrestricted legislative power.
• Republic of Iceland (1944–present)
  • In May 1991, Parliament became unicameral, operating in a unified chamber.
  • Iceland joins the European Economic Area in 1994, thus transferring significant legislative power to the European Union.