Alþingishúsið (Icelandic pronunciation: [ˈalˌθiɲcɪsˌhuːsɪθ], The Parliament House) is a classical 19th-century structure which stands by Austurvöllur in central Reykjavík, Iceland.

The building was designed by Ferdinand Meldahl and built using hewn Icelandic dolerite from 1880 to 1881.

[1] The reliefs on the tympanums of the four outermost windows on the first floor represent the four landvættir of Iceland: a dragon, a vulture, a giant and a bull, momentarily appeased by Ingólfur Arnarson when he first landed in Iceland.

Today, only the debating chamber, a few small meeting rooms and the offices of some of the senior parliamentary staff are actually located in Alþingishúsið.

Committee meeting rooms, parliamentarians' offices and most of Alþingi's secretariat are located in other buildings in the area around Austurvöllur.