Liga Premier is the third level professional division of Mexican football. Formerly known as Segunda División de México (1950–2017). It has 49 participating clubs, divided into two divisions (Serie A and Serie B). They compete from the fall to spring each season, promotion and relegation between each group, and promotion to Liga de Expansión MX and relegation to Liga TDP within the league system.
The champions of the 1993–94 Segunda División season was the last to be promoted to the Primera División. In 1994–95 season, the FMF created the Primera División A (renamed Ascenso MX in 2012) with 15 teams from the Segunda División, and all other teams remained in the league that continued to be called Segunda División but at the new third level of Mexican football.
Each season has Segunda División teams divided into geographic zones with matches predominantly among the teams of that group. Each season had one tournament.
In 2008, the FMF, with the approval of the chairmen of the clubs in the second and third levels, change the format of the league dividing the number of teams into two divisions, the Liga Premier and the Liga de Nuevos Talentos. Each of the new leagues was divided into geographic groups. The winning club could earn promotion to Primera División A, renamed Liga de Ascenso in 2009, provided their stadium and financial stability met the licensing requirements of Liga de Ascenso. From 2011 and 2016, no teams were relegated to Liga Premier, although Pumas Morelos was to be relegated in 2013 but they dissolved before they could play in the lower league. Promotion still occurred during these years provided the club was licensed to participate. In June 2016, Ascenso MX announced they would resume relegating teams. Since that year only Loros UdeC in 2017 and Murciélagos in 2018 were relegated from the upper level.
In 2020, the Ascenso MX was abolished and replaced by a new league that was called Liga de Expansión MX, two Liga Premier teams were invited to the new category: Tepatitlán and Tlaxcala, teams who had won their promotion in 2016 and 2018 but were rejected in the second level for not meeting the requirements to participate. Since that year, the requirements to be admitted to the second level have been tightened, so only one team, Durango, could be promoted in 2022, although it only remained in the Liga de Expansión for one year. In 2024, another team achieved promotion to the Liga de Expansión, Tampico Madero, although it also obtained its place in the second level division as a guest team and not as a full member.