Fifteen candidates contested the first round on 16 March, of which two later formally withdrew their bids before voting took place, but their names still had to remain on the ballot papers.

Maroš Šefčovič, the vice president of the European Commission for the Energy Union, who was running as an independent supported by the Direction – Social Democracy (SMER–SD) party, came in as the runner-up with 18.7% of the vote and earned a place in the run-off as well.

[4] However, Kiska announced on 15 May 2018 that he would not run for re-election, arguing that this move might end "the era of political confrontation" his country faced and citing a desire to spend more time with his family.

[17] For a candidacy to be valid, the Constitution of Slovakia requires the collection of 15,000 signatures of Slovak citizens, or the support of 15 of the 150 MPs in the legislature.

[65] Štefan Harabin ran on a platform of "traditional Slovak culture based on Christianity and family, formed by a man–father and woman–mother" and rejecting "gender ideology".

[67] During the campaign Harabin accused Muslim migrants of "killing and raping European women in Germany and France" and claimed his opponents wanted to destroy Slovak culture.

[68] According to Globsec, Harabin was the most favoured candidate by "pro-Kremlin disinformation channels" on Facebook, receiving 174 positive and no negative posts.

Maroš Šefčovič, the vice president of the European Commission for the Energy Union, who was running as an independent supported by the governing Smer-SD,[94] was the runner-up with 19% of the vote and earned the other place in the run-off.