As in the previous elections, no party won an outright majority in the 57-member Legislative Assembly. Only three parties secured more than 10 seats: National Liberation Party (PLN, which governed the country between 2006 and 2014), the National Restoration Party (PRN, comprising evangelical Christians) and outgoing President Luis Guillermo Solís' Citizens' Action Party (PAC). He was constitutionally barred from seeking a second consecutive presidential term.

In the presidential elections, no candidate secured the required 40 per cent of the votes to be elected in the first round, held in parallel with the parliamentary polls. On 1 April, Mr. Carlos Alvarado Quesada (PAC) defeated Mr. Fabricio Alvarado Muñoz (PRN) in the runoff election. On 8 May, the 38-year-old former Labour Minister was sworn in, thereby becoming the youngest ever President of Costa Rica. His deputy, Ms. Epsy Campbell, is the country's first Afro-Costa Rican Vice President.

President Alvarado Quesada formed a five-party coalition government comprising the PAC, the Social Christian Unity Party (PUSC), the PLN, the Broad Front (FA) and the 21st Century Curridabat (Curridabat Siglo XXI, which does not hold any seats in the Legislative Assembly). The Cabinet is made up of 16 men and 15 women. Meanwhile, on 1 May, Ms. Carolina Hidalgo Herrera (PAC), 35, became the youngest Speaker of the Legislative Assembly.

The 2018 elections were held shortly after a decision on 9 January by the Inter-American Court of Human Rights that signatories – including Costa Rica – must guarantee same-sex couples equal rights to marriage and property ownership. The decision pushed debate on gay marriage to the centre of the election campaign. Mr. Quesada (PAC) pledged to implement the decision while Mr. Muñoz (PRN) vowed to restore what he called traditional values by preventing gay marriage and restricting women's access to abortion. PLN's presidential candidate, Mr. Antonio Álvarez, promised to reform public salaries and to introduce a value-added tax.

In addition to "vertical parity" (men and women alternating within each list to ensure 50-50% gender parity), starting from the 2018 elections, political parties are expected (see note) to respect "horizontal parity" for the heads of the lists through their internal regulations. The parties fielding candidates in all seven provinces should submit lists headed by the less represented gender in at least three provinces.

Note:
The May 2016 resolution (3603-E8-2016) of the Election Commission (Tribunal Supremo de Elecciones) provided an unofficial interpretation of articles 2, 52 and 148 of the Electoral Code on the scope of the principle of parity for the head of the lists of candidates (without amending the Electoral Code itself), thereby indicating that all parties should adjust their candidate lists according to the principles of vertical and horizontal parity. A subsequent Electoral Commission resolution in September 2017 (5876-E1-2017) clarified that political parties should define mechanisms to ensure horizontal parity in their internal regulations, thereby making horizontal parity non-compulsory.