Oulu (Swedish: Uleåborg) is one of the 13 electoral districts of the Parliament of Finland, the national legislature of Finland. The district was established as Oulu Province South (Finnish: Oulun läänin eteläinen; Swedish: Uleåborgs läns södra) in 1907 when the Diet of Finland was replaced by the Parliament of Finland. It was renamed Oulu Province (Finnish: Oulun läänin; Swedish: Uleåborgs läns) in 1939 and Oulu in 1997. It is conterminous with the regions of Kainuu and North Ostrobothnia. The district currently elects 18 of the 200 members of the Parliament of Finland using the open party-list proportional representation electoral system. At the 2023 parliamentary election it had 393,643 registered electors.

Oulu Province South was one 16 electoral districts established by the Election Act of the Grand Duchy of Finland (Suomen Suuriruhtinaanmaan Vaalilaki) passed by the Diet of Finland in 1906.^[4] It consisted of the hundreds (kihlakunta) of Haapajärvi, Kajaani , Saloinen and Oulu and the rural municipality (maalaiskunta) of Oulu in the province of Oulu.^[4] The district's borders were redrawn in 1938 to be conterminous with the smaller Oulu Province, absorbing parts of Oulu Province North district.^[5] The district was renamed Oulu Province at the same time. The district was renamed Oulu in 1997.^[6][7]

Oulu currently elects 18 of the 200 members of the Parliament of Finland using the open party-list proportional representation electoral system.^[8][9] Parties may form electoral alliances with each other to pool their votes and increase their chances of winning seats.^[10][11] However, the number of candidates nominated by an electoral alliance may not exceed the maximum number of candidates that a single party may nominate.^[12] Seats are allocated using the D'Hondt method.^[13][14]