Voting for the Parliament was on the basis of universal suffrage, which comprised all nationals over 18 years of age, registered in Catalonia and in full enjoyment of their political rights.

The 135 members of the Parliament of Catalonia were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which included blank ballots—being applied in each constituency.

Seats were allocated to constituencies, corresponding to the provinces of Barcelona, Gerona, Lérida and Tarragona, with each being allocated a fixed number of seats:[1][2] In smaller constituencies, the use of the electoral method resulted in an effective threshold based on the district magnitude and the distribution of votes among candidacies.

The highest percentage figure in each polling survey is displayed with its background shaded in the leading party's colour.

The table below lists opinion polling on the perceived likelihood of victory for each party in the event of a regional election taking place.