The 2018 Irish presidential election took place on Friday, 26 October, between 7.00 a.m. and 10.00 p.m. President Michael D. Higgins, who was elected in 2011 with the support of the Labour Party, was seeking re-election to a second term as an independent. This was the first time since the 1966 election that an incumbent president faced a contest for a second term. Higgins was re-elected on the first count with nearly 56% of the vote, becoming the first president since Éamon de Valera to win a second term in a contested election (Seán T. O'Kelly in 1952, Patrick Hillery in 1983 and Mary McAleese in 2004 had been re-elected unopposed). He was inaugurated for his second term on 11 November.

The election was held on the same date as a referendum on blasphemy.

To stand for election as president, candidates must:

If a member of the Oireachtas or a County or City council nominate more than one candidate, only the first nomination paper received from them will be deemed valid. Presidential elections are conducted in line with Article 12 of the Constitution and under the Presidential Elections Act 1993, as amended. The President of Ireland is elected through Instant-runoff voting. All Irish citizens entered on the current electoral register are eligible to vote. Under the Electoral (Amendment) Act 2011, there is a spending limit by each candidate of €750,000. Candidates who are elected or who reach 12.5% of the vote on their elimination are entitled to a reimbursement of expenses up to €200,000.

On 28 August the Minister for Housing, Planning and Local Government, Eoghan Murphy, signed the order for the presidential election, specifying the nomination period as between 10 a.m. on 30 August and 12 noon on 26 September 2018.

On 10 July 2018, incumbent president Michael D. Higgins declared that he would exercise his right to nominate himself as a candidate for the presidential election. Higgins had said in 2011 that he intended to serve one term only, but changed his mind over the course of his term. Higgins's website and social media accounts became active on 17 September, having been dormant since his inauguration in November 2011. He formally nominated himself on 24 September.

Sinn Féin was the only party to select a candidate. With 28 Oireachtas members (22 TDs and six Senators), the party could nominate a candidate without the need for additional nominations from independents to reach the requirement of 20 Oireachtas members, as they had required in 2011. Nearly all other parties in the Oireachtas supported the re-election of Michael D. Higgins. People Before Profit declined to support any candidate in the election. Independent TD Michael Fitzmaurice had tried to gather the support of other Independent TDs and Senators to support a candidate, but was unsuccessful. Nineteen were willing to be involved in his effort to find a candidate, one short of the twenty required to be nominated. Eleven Oireachtas members signed a nomination form for Gemma O'Doherty, nine short of the required number.

18 local authorities passed resolutions supporting a particular candidate, while the remaining 13 either passed no resolution or passed a resolution declining to nominate any candidate. Candidates needed the support of at least four local authorities to be a candidate in the election.