As a result of the election, the Spanish Socialist Workers' Party (PSOE) emerged as the largest political party in a Madrilenian regional election for the first time since 1987, but failed short of securing a majority together with Íñigo Errejón's Más Madrid and Unidas Podemos, the latter of which barely surpassed the 5% threshold to win seats in the Assembly.

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

[2] All members of the Assembly of Madrid 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 regionally.

[1][3][4] The president had the prerogative to dissolve the Assembly of Madrid 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.

[6] On 21 March 2018, it transpired that President Cristina Cifuentes could have obtained a master's degree in the King Juan Carlos University through fraudulent means.

[9][10] Preliminary probing revealed evidence of possible criminal offenses that were subsequently put under investigation of the judiciary, questioning Cifuentes's continuity as regional premier.

[17][18] Cifuentes's scandal joined many others in a long list of corruption cases beleaguering the ruling People's Party (PP) in Spain that ended up with Prime Minister Mariano Rajoy's downfall on 1 June through a vote of no confidence in the Congress of Deputies.

[25][26] Podemos leaders also urged Errejón to resign his seat in the Congress of Deputies,[27] considering his move as "deceitful" and "a betrayal" to the party.

[28] On 21 January, Errejón vacated his seat in the Congress,[29][30] but still called for Podemos, IU and Equo to join the Más Madrid platform.