The ruling People's Party (PP) emerged once again as the largest political force in the region, but it saw a substantial drop in its vote support and the loss of the absolute majority it had held almost uninterruptedly since 1995—with a brief interlude in 2003—.

However, as both the Spanish Socialist Workers' Party (PSOE) and newcomer Podemos fell one seat short of an absolute majority, it meant that the PP could remain in government through an agreement with liberal Citizens (C's).

[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.

[6] Opinion polls from 2012 predicted a drop in vote support for the PP, to the point that it could lose the absolute majority it had enjoyed almost uninterruptedly since 1995.

[7] Podemos's growth in opinion polls since mid-to-late 2014 at the expense of the PSOE's vote inspired fears within the party that it could be displaced to third place both regionally and nationally.

[23] Ángel Gabilondo, former Education minister in José Luis Rodríguez Zapatero's cabinet from 2009 to 2011, was selected as PSOE's leading candidate in the region replacing Gómez on 21 February 2015.

[25] Luis García Montero, a Spanish poet and literary critic, was selected to replace Sánchez' as IU candidate to the Community of Madrid.

[14] The PP had not yet proclaimed a candidate as of February 2015, despite incumbent President Ignacio González being widely presumed to stand for a second term in office.

[26] On 2 March 2015, Spanish newspaper El Mundo's headlines pointed out that González' had asked National Police officers to withhold information over an ongoing investigation on him about a possible tax fraud in the purchase of a luxury penthouse.

[28] However, rumours arose in the media that the party's leadership had withdrawn their support from González and expected him to eventually give up on his intention to run.

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