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

The 75 members of the Basque Parliament were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of five percent of valid votes—which included blank ballots—being applied in each constituency.

[1][2] The lehendakari had the prerogative to dissolve the Basque Parliament at any given time and call a snap election, provided that no motion of no confidence was in process.

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

The "Lead" column on the right shows the percentage-point difference between the parties with the highest percentages in a poll.