The Parliament of Finland (Finnish: Suomen eduskunta [suomen eduskunt]; Swedish: Finlands riksdag [finlnds riksd()]) is the unicameral and supreme legislature of Finland, founded on 9 May 1906. In accordance with the Constitution of Finland, sovereignty belongs to the people, and that power is vested in the Parliament. The Parliament consists of 200 members, 199 of whom are elected every four years from 13 multi-member districts electing 7 to 36 members using the proportional D'Hondt method. In addition, there is one member from land.

Legislation may be initiated by either the Government or one of the members of Parliament. The Parliament passes legislation, decides on the state budget, approves international treaties, and supervises the activities of the government. It may bring about the resignation of the Finnish Government, override presidential vetoes, and alter the constitution. To make changes to the constitution, amendments must be approved by two successive parliaments, with an election cycle in between, or passed as an emergency law with a 167/200 majority. Most MPs work in parliamentary groups which correspond with the political parties. The Parliament currently comprises nine parliamentary groups. Since the establishment of the Parliament in 1905, the parliamentary majority has been held once by a single party: the Social Democrats in the 1916 election. Thus, for the Government to gain a majority in the Parliament, coalition governments are favored. These are generally formed by at least two of the three historically major parties: the Social Democrats, Centre, and National Coalition. Ministers are often but not necessarily MPs. The Parliament meets in the Parliament House (Finnish: Eduskuntatalo, Swedish: Riksdagshuset), which is located in central Helsinki.

The most recent parliamentary election took place on 14 April 2019. The Social Democratic Party, the Centre Party, the Green League, the Left Alliance, and the Swedish People's Party cooperated to form the Rinne Cabinet, a centre-left coalition government. This was succeeded in December 2019 by the Marin Cabinet which is made up of the same parties.

Unicameralism (from uni- "one" + Latin camera "chamber") is a type of legislature, which consists of one house or assembly, that legislates and votes as one.Unicameral legislatures exist when there is no widely perceived need for multicameralism. Many multicameral legislatures were created to give separate voices to different sectors of society. Multiple houses allowed, for example, for a guaranteed representation of different social classes (as in the Parliament of the United Kingdom or the French States-General). Sometimes, as in New Zealand and Denmark, unicameralism comes about through the abolition of one of two bicameral chambers, or, as in Sweden, through the merger of the two chambers into a single one, while in others a second chamber has never existed from the beginning.