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 president had the prerogative to dissolve the Cortes of Castile and León and call a snap election, provided that no motion of no confidence was in process, no nationwide election was due and some time requirements were met: namely, that dissolution did not occur either during the first legislative session or within the legislature's last year ahead of its scheduled expiry, nor before one year had elapsed since a previous dissolution.

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