The Nation Alliance (formed of the Republican People's Party (CHP) and the İYİ Party) fielded their initial candidate Ekrem İmamoğlu, who ran a positive campaign under the slogan Her Şey Çok Güzel Olacak (Everything will be fine). The governing People's Alliance (formed by the AKP and the Nationalist Movement Party) re-nominated their initially unsuccessful candidate Binali Yıldırım. The non-aligned Peoples' Democratic Party (HDP) did not field their own candidate and announced their support for İmamoğlu. The election featured a televised debate between the two main candidates, a first in Turkey since 2002. Campaigning focused highly on rival accusations of misconduct during and after the initial March 2019 election, during which both sides alleged that they had been a victim of the other's antics.
The results showed a substantial swing in favour of İmamoğlu, who multiplied his initial 13,700-vote margin of victory 57-fold to win 54.2% of the vote against Yıldırım's 45.0%. The opposition's victory defied opinion polls, which predicted a much narrower victory, and was a record in the history of Istanbul local elections in terms of both popular vote and percentage share. İmamoğlu also won pluralities in 28 of Istanbul's 39 districts. Yıldırım, on the other hand, lost 11 districts he had won in March and saw a 4 percent decrease in his previous vote share, conceding defeat soon after indicative results became public. The result was seen as a huge blow to President Recep Tayyip Erdoğan, who had once said that if his party "lost Istanbul, we would lose Turkey." Commentators viewed the result as a backlash against Erdoğan, the initial annulment of the March vote (which was largely seen as an anti-democratic manoeuvre), economic mismanagement and negative campaigning. It was also seen as a backfire against the government's last-ditch attempt to involve the outlawed Kurdistan Workers' Party (PKK)'s imprisoned leader Abdullah Öcalan in the process, in an attempt to convince HDP voters to boycott the election.
The opposition's landslide was characterised as the "beginning of the end" for Erdoğan, with international commentators calling the re-run a huge government miscalculation that led to a potential İmamoğlu candidacy in the next scheduled presidential election. It is suspected that the scale of the government's defeat could provoke a cabinet reshuffle and early general elections, currently scheduled for June 2023.
After the local elections were held on 31 March 2019, the Chairman of the Supreme Electoral Council (YSK), Sadi Güven, announced that Ekrem İmamoğlu received 4,159,650 votes and that he was ahead of Justice and Development Party's (AKP) Istanbul mayoral candidate Binali Yıldırım. The Istanbul Provincial Organization of the AKP demanded a re-count of invalid votes and the correction of ballot records on 2 April, which was approved by the Supreme Electoral Council. At the conclusion of the re-counting process on 17 April 2019, it was announced that Ekrem İmamoğlu had completed the election with 4,169,765 votes, 13,729 votes ahead of his rival Binali Yıldırım, who received 4,156,036 votes. On the same day, İmamoğlu began his term by receiving his certificate of election from the Supreme Electoral Council's İstanbul Provincial Electoral Council.
On 6 May 2019, in a 7-to-4 decision, the YSK ruled that the Istanbul mayoral election shall be annulled, and that it shall be repeated on 23 June 2019. This decision was based on the objections raised by the AKP regarding the fact that despite the law, some balloting committee presidents and members were not public officials. Despite the decision, the President of the YSK Sadi Güven was one of the four members who voted against annulment. He later publicly stated that he was not in favour of renewing the election.
The Supreme Electoral Council determined the electoral schedule based on its decision on 6 May 2019 to annul the original election and repeat it on 23 June 2019:
15 May 2019: The deadline for the submittal of a list of all public servants that will serve in each district to the relevant district election committee centers.
20 May 2019: The determination, based on a lottery, of the balloting committee presidents and members, from among the submitted list of public servants.
21 May 2019: The distribution of the list of the balloting committee presidents and members to political parties, if requested.
23–24 May 2019: The deadline for the submittal of possible objections regarding the make-up of the balloting committees.
24 May 2019: The deadline for the period in which political parties can change to their candidates.
25 May 2019: The deadline for decisions to be made by the district electoral councils regarding the objections to the make-up of the balloting committees.
26 May 2019: The deadline for objections regarding the decisions made by the district electoral councils to be submitted to the Istanbul Provincial Electoral Council.
27 May 2019: The announcement of the finalized candidate lists, the printing of the unified ballots and their distribution to the district electoral councils, and the beginning of distribution of the voter information documents.
29 May 2019: The completion of the establishment of the balloting committees.
13 June 2019: The beginning of election propaganda and of certain prohibitions.
16 June 2019: The deadline for the completion of distribution of the voter information documents.
18 June 2019: The annotation of information regarding restricted voters to the voter lists.
19 June 2019: The completion of the replication of the ballot box voter lists.
22 June 2019: The ending of election propaganda at 18:00.
23 June 2019: The beginning of the voting process at 8:00, and its completion at 17:00.
The Supreme Electoral Council announced that the electoral roll would be exactly the same as the electors in the March 2019. Since the vote was a re-run, voters who turned 18 between 31 March and 23 June 2019 would not be included on the electoral roll. The YSK did, however, remove individuals with mental disabilities from voter lists. This was due to numerous complaints from all parties in the March local elections that mentally impaired individuals unable to exercise free thought were exploited for their vote. As a result, the Istanbul electorate fell from 10,570,939 to 10,570,354 (including deaths and convictions during this time).
After the annulment of the 31 March elections, the Democratic Left Party (DSP) candidate Muammer Aydın, the Independent Turkey Party (BTP) candidate Selim Kotil, the Democratic Party candidate Ersan Gökgöz, the Turkish Communist Party candidate Zehra Güner Karaoğlu, the Worker's Movement Party-supported independent candidate Özge Akman, the Turkish Communist Movement-supported independent candidate Aysel Tekerek, and the independent candidate Hazer Oruç Kaya all announced that they would not stand in the upcoming election.
The Felicity Party (Saadet Party) candidate Necdet Gökçınar, the Patriotic Party (Vatan Party) candidate Mustafa İlker Yücel, and the independent candidates Doğan Duman and Muhammet Ali Canca, conversely announced that they would participate in the Istanbul mayoral election that would be repeated on 23 June 2019.
On 27 May 2019, the finalized candidate list for the 23 June 2019 election was announced. In the list announced by the Istanbul Provincial Electoral Council, there are 17 independent candidates aside from the partied candidates Ekrem İmamoğlu, Binali Yıldırım, Necdet Gökçınar, and Mustafa İlker Yücel.
In the articles published on 9 May 2019 regarding the AKP's strategy, it was said that the AKP would go door-to-door to convince undecided voters and those who did not vote on 31 March, that the AKP would soften its rhetoric, that projects regarding Istanbul and its districts would be emphasized, and that the AKP would participate in joint rallies with the MHP. Aside from these efforts, president and AKP leader Recep Tayyip Erdoğan would join iftar dinners throughout Ramadan, make house visits to voters, and hold rallies in each of the 39 districts of Istanbul. An election coordination center was created under the scope of these strategies, and Mehmet Özhaseki, AK Party's candidate for Ankara mayor on 31 March 2019 was chosen to lead this operation.
As part of their election campaign, AKP's goals were:
To explain the reasons for the annulment of the election to the voters in a convincing manner.
To call all 2,300,000 AKP members who are eligible to vote in Istanbul by telephone, and to remind them that they absolutely need to vote.
A different rhetoric was used towards the estimated 400,000 to 700,000 AKP voters who did not vote for Binali Yıldırım on 31 March as a reaction against the party's policies. In this context, the statements by government spokesperson Mahir Ünal's and AKP group deputy chairman Numan Kurtulmuş's statements drew special attention.
During the campaign for the election on 31 March, the AKP along with its partner MHP emphasized the "survival problem" in its rhetoric. Afterwards, the AKP determined that many conservativeKurds who had previously voted for the AKP had not voted on 31 March, due to the fact that the rhetoric associating Kurds with terrorism during the campaign had been highly successful. Accordingly, the AKP decided to proceed with a separate effort for the roughly 230,000 conservative Kurds who did not vote on 31 March. AKP decided to campaign by messaging that they would "fix their mistakes" to people such as opinion leaders, business people, NGOs in the southeastern provinces as well as in Istanbul. Through this, the AKP planned to communicate directly with the Kurdish voters. On the other hand, the AKP appealed to the MHP, which supports Binali Yıldırım in the election, not to campaign in Istanbul.
Binali Yıldırım visited Diyarbakır on 6 June in order to gain the support of Kurdish voters in Istanbul. There, he welcomed those who came to listen to him using Kurdish words, claimed that there were "members of parliament from Kurdistan in the inaugural Grand National Assembly of Turkey, and pronounced the name of the PKK differently than the way that it is commonly pronounced, all of which drew a reaction. These actions by Yıldırım in Diyarbakır were criticised by İyi Party leader Meral Akşener as "first calling Kurds terrorists, and then going to Diyarbakır and crying to get their votes in Istanbul", and by MHP leader Devlet Bahçeli as "there is no Kurdistan or Lazistan in Turkey. Neither will there be in the future. If there are who wish that there would be, they will always find the Nationalist-Idealist movement". Bahçeli's statement was ignored by media organizations close to the AK Party. Co-leader of the HDPSezai Temelli also criticised the hypocrisy Yıldırım's actions.
On 6 May 2019, the lawyers of imprisoned PKK leader Abdullah Öcalan were allowed to visit Öcalan. This was followed by the lifting of the ban on the visitation of Öcalan by Justice Minister Abdülhamit Gül. These actions, combined with a shift in rhetoric on Öcalan by the Anadolu Agency from pre-31 March "head terrorist" to simply "İmralı", the referral of Öcalan as "estimable Öcalan" by Presidential Security and Foreign Policy Council member Burhanettin Duran, as well as Öcalan's request for an end to the hunger strikes started for the betterment of his imprisonment conditions on 26 May all caused speculation of cooperation between the AK Party and Öcalan. On the other hand, speculation was also made that the purpose of the meetings with Öcalan was to cause a drop in İmamoğlu's votes by either having the HDP name a candidate for mayor, or by having the HDP boycott the election. Conversely, MHP leader Bahçeli said, in regards to Öcalan's visitation by his lawyers, that "If you ask me, he should meet with his lawyer".
After the annulment of the 31 March elections, Binali Yıldırım gave the response of "very simple, because they stole" to a citizen who asked about the annulment. Following this, the Justice and Development Party (AK Party) began to regularly allege that the Republican People's Party (CHP) had stolen votes. As part of this, President Erdoğan claimed that there existed footage proving that the CHP had committed vote theft, but this footage never surfaced. However, despite this, Erdoğan continued to raise this allegation.
On the other hand, in regards to the accusation that the CHP stole votes, Yıldırım alleged that balloting council presidents had not given the relevant ballots to those that they identified as AK Party voters in the 31 March elections. Meanwhile, Minister of the Interior Süleyman Soylu claimed that the votes were stolen after the tabulation of the votes.
After the absence of vote theft in the reasoning for the annulment of the election by the Supreme Electoral Council (YSK), the AK Party's allegations were criticised by the CHP. In light of this, Yıldırım claimed that he "had to say that they stole", due to the reasoning that he could not make his voice heard during the campaign.
Members of the AK Party made certain accusations during the campaign towards Ekrem İmamoğlu and the CHP:
President Erdoğan said that "this is Istanbul, this is not Constantinople, there are some that want to see it as such. We have 22 days against those that want to see it as such".
Regarding the election, AK Party general vice president Mehmet Özhaseki said that "[their] side is on the side of the nation, of the government, of people and of service. If you look to the other side, you will see FETÖ's scoundrels and PKK's murderers".
AK Party's Erzurum member of parliament İbrahim Aydemir said that should Ekrem İmamoğlu win the election, that "the non-believers' idols will be erected" in Istanbul.
AK Party's Erzurum member of parliament Selami Altınok said that should Ekrem İmamoğlu win the election, that İSPARK would be given to the HDP.
AK Party's Istanbul member of parliament Ahmet Hamdi Çamlı compared voters who voted for İmamoğlu to the "sick".
During the annulment process, there were criticisms of the Justice and Development Party (AK Party) from party members and from those who were ideologically close to the party. Former AK Party prime minister Ahmet Davutoğlu criticised the decision to annul, saying that "the YSK's decision to annul has caused an erosion to our most basic principles". Following this, referring to the implication made by a television program that he is a traitor, Davutoğlu responded that "the day will come when we will find out who protected the inheritance, and who betrayed it". Later, Davutoğlu said that "everything can be lost, and then won again. Power can be lost and then won again. There is no tomorrow for those who lose hope. Don't be afraid to talk".
Meanwhile, other members of the AK Party brought certain criticisms towards the annulment and the campaign run by the AK Party:
AK Party Istanbul member of parliament Mustafa Yeneroğlu said that the government needs to listen to the criticisms from the public, and that steps should be taken to ensure that a pluralistic democracy and a liberal constitutional state can grow.
Former AK Party member of parliament Mehmet Ocaktan claimed that the AK Party's representative in the YSK is a member of FETÖ.
AK Party Ardahan member of parliament Orhan Atalay characterized the Tarawih prayers organised by the Muftiate of Istanbul for the anniversary of the Conquest of Istanbul, which President Erdoğan joined, as being "palace style".
The interview given by AK Party general vice president Azmi Ekinci wherein Ekinci criticised the party's strategy in the 31 March elections was removed.
In response to these developments, President Erdoğan said that "as the Turkish nation gives one of the most critical struggles in its history, we will not give permission to those who want to implement their own agendas at the cost of our party's weakness". In addition to this, the decision to assign duties to those who have not been recently active but who are known in the AK Party, such as Abdülkadir Aksu, Sadık Yakut, Mevlüt Uysal, Faruk Çelik, and Bülent Arınç was seen as measures to stop the intra-party opposition.
İmamoğlu, who won the elections held on 31 March, but whose certificate of election was cancelled by the annulment of the election, declared that they wouldn't boycott the election and that they would compete immediately after the decision to annul. After this declaration, İmamoğlu met with voters in a different district of Istanbul every day, joined iftars, and made speeches.
It was announced that İmamoğlu's victimhood would be emphasized, that even the candidates who lost would be active, that large rallies would not be held, and that house visits would be made.
A news bureau would be established as an alternative to the Anadolu Agency in the 23 June elections, and that the results would be published live as the counts are completed.
İmamoğlu indicated that he would continue to use the title "Mayor of Istanbul".
A donation campaign was established to fund the election campaign. While the donations made in the first day reached ₺5,000,000, the donations made in one week reached over ₺10,000,000 from 500,000 donors, of which 340,000 were from domestic donors. As of 26 May, the total amount of donations made to the campaign exceeded ₺15,000,000.
It was decided that only five people (Ekrem İmamoğlu, CHP İstanbul Provincial President Canan Kaftancıoğlu, and CHP General Vice Presidents Oğuz Kaan Salıcı, Seyit Torun, and Onursal Adıgüzel) would be assigned to electoral coordination.
While a group of members of parliament would be working in the Grand National Assembly (TBMM), other members of parliament were assigned to Istanbul.
It was decided that there would be a campaign to get the 1,700,000 people who did not vote on 31 March to vote. As part of this, a "bring your neighbour who didn't vote on 31 March to the ballot box" campaign was established.
It was announced that slogans other than "Her şey çok güzel olacak" (Everything will be fine) would be used in the campaign.
The following table is detailing the preliminary results of the Istanbul Mayoral Election, with more than 99% of the ballots counted. Official results will be released by the Supreme Electoral Council. Both Yıldırım and Erdoğan acknowledged the defeat and congratulated Ekrem İmamoğlu on his re-election as Mayor of Istanbul.