[2] For the first time since 1893, the AFA did not organise the championship, now being administrated by the Superliga Argentina de Fútbol.
Four teams (Aldosivi, Atlético de Rafaela, Quilmes and Sarmiento) were relegated to the Primera B Nacional Championship in the previous tournament.
Boca Juniors, who were the defending champions, won their thirty-third league title with one match to spare after a 2–2 draw against Gimnasia y Esgrima (LP) on 9 May 2018.
[4] As a result, Boca Juniors qualified for both the 2019 Copa Libertadores and the 2018 Supercopa Argentina.
The additional match against the main rival team in the so-called "Fecha de Clásicos" was not played in this season.