A municipal election was held in Madrid on 24 May 2015 to elect the 10th City Council of the municipality. All 57 seats in the City Council were up for election. It was held concurrently with regional elections in thirteen autonomous communities and local elections all across Spain.

Leading the People's Party (PP) local list was Esperanza Aguirre, former president of the Community of Madrid (2003–2012), president of the Senate of Spain (1999–2002) and minister of Education and Culture (1996–1999), as well as the leader of the regional PP branch since 2004. Mayor Ana Botella, who succeeded Alberto Ruiz-Gallardón early into his term in December 2011, had declined re-election in September 2014. The election was an unexpectedly close race between Aguirre's PP and former judge Manuela Carmena's Podemos-supported Ahora Madrid () platform. The collapse in the PP vote and the loss of its absolute majority allowed Carmena to gain power through an alliance with the Spanish Socialist Workers' Party (PSOE), resulting in the first left-wing government in the city since 1989.

The PSOE suffered heavily from tactical voting to Ahora Madrid after it became apparent throughout the campaign that the left-of-centre vote was coalescing around Carmena's coalition. The newcomer liberal Citizens () party also entered the City Council for the first time, collecting votes disenchanted with the PP and replacing Union, Progress and Democracy (UPyD) as the main centrist local force. United Left (IU) fell below the 5% threshold and failed to gain any representation for the first time in history.

Overview Under the 1978 Constitution, the governance of municipalities in Spain—part of the country's local government system—was centered on the figure of city councils (), local corporations with independent legal personality composed of a mayor, a government council and an elected legislative assembly.; . The mayor was indirectly elected by the local assembly, requiring an absolute majority; otherwise, the candidate from the most-voted party automatically became mayor (ties were resolved by drawing lots).; . In the case of Madrid, the top-tier administrative and governing body was the City Council of Madrid..

Date The term of local assemblies in Spain expired four years after the date of their previous election, with election day being fixed for the fourth Sunday of May every four years. The election decree was required to be issued no later than 54 days before the scheduled election date and published on the following day in the Official State Gazette (BOE).. The previous local elections were held on 22 May 2011, setting the date for election day on the fourth Sunday of May four years later, which was 24 May 2015.

Local assemblies could not be dissolved before the expiration of their term, except in cases of mismanagement that seriously harmed the public interest and implied a breach of constitutional obligations, in which case the Council of Ministers could—optionally—decide to call a by-election..

Elections to the assemblies of local entities were officially called on 31 March 2015 with the publication of the corresponding decree in the BOE, setting election day for 24 May..

Electoral system Voting for local assemblies was based on universal suffrage, comprising all Spanish nationals over 18 years of age, registered and residing in the municipality and with full political rights (provided that they had not been deprived of the right to vote by a final sentence, nor were legally incapacitated), as well as resident non-national European citizens, and those whose country of origin allowed reciprocal voting by virtue of a treaty.; ; .

Local councillors were elected using the D'Hondt method and closed-list proportional voting, with a five percent-threshold of valid votes (including blank ballots) in each municipality.. Each municipality was a multi-member constituency, with a number of seats based on the following scale:.

Population Councillors <100 3 101–250 5 251–1,000 7 1,001–2,000 9 2,001–5,000 11 5,001–10,000 13 10,001–20,000 17 20,001–50,000 21 50,001–100,000 25 >100,001 +1 per each 100,000 inhabitants or fraction+1 if total is an even number

The law did not provide for by-elections to fill vacant seats; instead, any vacancies arising after the proclamation of candidates and during the legislative term were filled by the next candidates on the party lists or, when required, by designated substitutes..

Parties and candidates The electoral law allowed for parties and federations registered in the interior ministry, alliances and groupings of electors to present lists of candidates. Parties and federations intending to form an alliance were required to inform the relevant electoral commission within 10 days of the election call, whereas groupings of electors needed to secure the signature of a determined amount of the electors registered in the municipality for which they sought election, disallowing electors from signing for more than one list. In the case of Madrid, as its population was over 1,000,001, at least 8,000 signatures were required.. Additionally, a balanced composition of men and women was required in the electoral lists, so that candidates of either sex made up at least 40 percent of the total composition..

Below is a list of the main parties and alliances which contested the election:

Candidacy Parties andalliances Leading candidate Ideology Previous result Vote % Seats PP Esperanza Aguirre ConservatismChristian democracy 49.7% PSOE Antonio Miguel Carmona Social democracy 23.9% IUCM–LV Raquel López SocialismCommunism 10.7% UPyD David Ortega Social liberalismRadical centrism 7.9% C's Begoña Villacís Liberalism 0.2% AhoraMadrid Manuela Carmena ProgressivismParticipatory democracy colspan="2"

Campaign Electoral debates were held in Telemadrid between the candidates of the PP, PSOE, IU, UPyD, Vox, Citizens and Ahora Madrid in the last week of campaign, between 18 and 20 May. The most expected and tense moment came with the debate between PP candidate Esperanza Aguirre and AM Manuela Carmena, as the most-likely candidates to become the next Mayor of the city. Aguirre immediately accused Carmena of saying in the past that "ETA members had suffered a lot", trying to link the former judge with the terrorist group, as well as trying to discredit Carmena's career in the judiciary, which was seen as a furious attack of Aguirre on Carmena. The latter, visibly surprised, counterattacked responding that Aguirre was acting arrogantly and contemptuous to others and accusing her of allowing corruption to spread during her tenure as president of Madrid. "Please go, you've caused a lot of harm" said Carmena to Aguirre.

In the last days of the campaign, especially following her debate with Aguirre, several celebrities such as actors Pilar Bardem, Carlos Bardem, Loles León, Goya Toledo, Paco León, playwright Cristina Rota, lawyer and former politician Cristina Almeida and journalist Ernesto Ekaizer expressed their support for Carmena's candidacy, with actress Eva Hache going on to say through the Twitter social network that "I don't know if we are Manuela but surely we are not the other [in reference to Aguirre]. VOTE." Carmena had also received the support of dozens of artists who created drawings in support of Carmena's and Ahora Madrid candidacy, with the drawings themselves becoming viral in the social networks. Following the Telemadrid debate, after which Aguirre was highly criticised for her aggressive behaviour towards Carmena, supporters cast the drawings next to Aguirre's home in Malasaña. On 21 May, a Carmena's act in the center of Madrid exceeded its capacity, originally scheduled for 800 people, resulting in the closing of a street and in Carmena herself apologizing to the around 1,500 people outside that were not able to enter.

Opinion polls The tables below list opinion polling results in reverse chronological order, showing the most recent first and using the dates when the survey fieldwork was done, as opposed to the date of publication. Where the fieldwork dates are unknown, the date of publication is given instead. The highest percentage figure in each polling survey is displayed with its background shaded in the leading party's colour. If a tie ensues, this is applied to the figures with the highest percentages. The "Lead" column on the right shows the percentage-point difference between the parties with the highest percentages in a poll.

Voting intention estimates The table below lists weighted voting intention estimates. Refusals are generally excluded from the party vote percentages, while question wording and the treatment of "don't know" responses and those not intending to vote may vary between polling organisations. When available, seat projections determined by the polling organisations are displayed below (or in place of) the percentages in a smaller font; 29 seats were required for an absolute majority in the City Council of Madrid.

Polling firm/Commissioner Fieldwork date Sample size Turnout Lead 2015 municipal election 24 May 2015 68.9 34.6 15.3 1.7 1.8 11.4 31.8 2.8 TNS Demoscopia/RTVE–FORTA 24 May 2015?? 31.9 15.5 2.0 1.5 10.8 33.8 1.9 GAD3/Antena 3 11–22 May 2015???? – –? ?? PP 20 May 2015????? –? ?? Idea Nomina Data/Público 17 May 2015 1,000? 34.0–36.0 17.0–19.0 3.0–4.5 1.5–2.5 15.0–17.0 22.0–25.0 11.0–12.0 Metroscopia/El País 13–14 May 2015 1,000 70 29.7 17.2 4.3 0.8 16.4 27.8 1.9 NC Report/La Razón 13–14 May 2015 600? 35.2 20.1 4.1 2.8 16.2 16.9 15.1 Sigma Dos/El Mundo 12–13 May 2015 800? 36.4 19.2 4.6 1.6 14.7 20.2 16.2 JM&A/Público 12 May 2015???? – –? ?? Sigma Dos/Mediaset 4–7 May 2015?? 36.9 20.3 3.6 1.3 16.1 17.6 16.6 MyWord/Cadena SER 29 Apr–6 May 2015 801? 34.4 17.6 2.9 1.1 17.0 21.6 12.8 JM&A/Público 3 May 2015?? 33.4 20.3 5.4 1.2 15.3 20.5 12.9 InvyMark/laSexta 27–30 Apr 2015?? 36.1 18.5 4.3 1.9 15.5 17.3 17.6 Metroscopia/El País 27–28 Apr 2015 600 69 34.6 17.2 4.2 0.6 16.9 24.3 10.3 Cámara de Comercio 23 Apr 2015?? 35.3 18.5 6.7 1.4 11.8 23.6 11.7 Deimos Estadística 16–23 Apr 2015 605 77.1 37.6 26.1 4.3 2.3 14.8 12.3 11.5 GAD3/ABC 13–20 Apr 2015 608? 34.5 21.2 4.6 1.1 15.6 18.2 13.3 Encuestamos 2–20 Apr 2015 600? 32.9 22.1 4.7 0.8 14.8 21.8 10.8 CIS 23 Mar–19 Apr 2015 927? 34.5 18.8 4.2 3.2 14.9 20.8 13.7 Sigma Dos/Mediaset 14–16 Apr 2015?? 36.8 17.5 4.9 1.4 16.8 18.6 18.2 PP 3 Apr 2015?? 34.0–36.0 18.0–19.0 5.0–6.0 2.0–3.0 14.0–16.0 21.0–22.0 13.0–14.0 Sigma Dos/El Mundo 25–26 Mar 2015 800? 34.5 18.7 6.4 1.4 15.1 21.2 13.3 Metroscopia/El País 19–20 Feb 2015?? 31.0 22.5 4.5 2.1 14.2 21.9 – 8.5 PP 18 Feb 2015??????? ? –??????? ? –? InvyMark/laSexta 12–13 Feb 2015?? 40.1 21.5 5.0 4.8 6.5 14.9 – 18.6 Metroscopia/El País 11 Feb 2015?? 29.5 24.7 3.8 4.1 11.7 22.6 – 4.8 PP 4 Feb 2015???? – –? ? –? Metroscopia/El País 26 Jan 2015?? 28.7 22.0 8.3 7.2 8.5 18.6 – 6.7 Sigma Dos/El Mundo 1–14 Nov 2014 800? 31.4 19.5 6.8 7.7 4.3 24.6 – – 6.8 Llorente & Cuenca 31 Oct 2014?????? –? – –? GAD3/ABC 5–11 Sep 2014 600 71 42.1 14.4 7.7 10.4 5.3 15.1 – – 27.0 2014 EP election 25 May 2014 50.0 32.4 18.2 10.3 9.6 4.7 10.5 – – 14.2 Metroscopia/El País 24–28 Apr 2014 600 60 32.5 23.4 20.8 11.6 – – – – 9.1 InvyMark/laSexta 21 Apr 2014?? 39.4 23.5 14.8 15.6 – – – – 15.9 Metroscopia/El País 13 May 2013 600 55.2 30.2 22.1 20.5 11.2 – – – – 8.1 GAD3/ABC 9–13 Jan 2012 400? 51.2 22.8 8.1 9.2 – – – – 28.4 2011 general election 20 Nov 2011 75.2 51.6 25.7 7.9 9.8 – – – – 25.9 2011 municipal election 22 May 2011 67.2 49.7 23.9 10.7 7.9 0.2 – – – 25.8

Voting preferences The table below lists raw, unweighted voting preferences.