The legislature was reduced from 130 seats to 100, making all existing parties to lose ground.

[1] At the 2016 election, held on 23 October 2016, the Social Democrats, the Greens and the Liberals won the election, while the Christian Democratic People's Party, the Green Liberals and the FDP lost popular vote and seats in the Grand Council.

Like other legislatures in Switzerland, elections use party list proportional representation.

The communities of Riehen and Bettingen each form a constituency, whilst the city of Basel is divided into three constituencies: the area north of the river Rhine is Kleinbasel, whilst the remaining Grossbasel is arbitrarily split into Grossbasel East and Grossbasel West.

Election result Distribution of seats Footnotes 1 SD: until 2004: SD, 2008: SD/EDU 2 EVP: until 2004: VEW, 2008: EVP 3 GB: 1996: GB, 2000: BastA (Greens and FraP), 2004 and 2008: GB 4 1988: additionally: PvA: 2.0% 5 VA: 2 seats, AB (Aktives Bettingen): 1 seat