The Cortes of Castile and León were the devolved, unicameral legislature of the autonomous community of Castile and León, having legislative power in regional matters as defined by the Spanish Constitution and the Castilian-Leonese Statute of Autonomy, as well as the ability to vote confidence in or withdraw it from a regional president.

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

All members of the Cortes of Castile and León 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.

[1][2][4] The Cortes of Castile and León could not be dissolved before the date of expiry of parliament except in the event of an investiture process failing to elect a regional president within a two-month period from the first ballot.

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