The Primeira Liga (; English: First League), also known as Liga NOS for sponsorship reasons, is the top professional association football division of the Portuguese football league system. It is organised and supervised by the Liga Portuguesa de Futebol Profissional. As of the 2014–15 season, the Primeira Liga is contested by 18 teams, with the two lowest placed teams being relegated to the Segunda Liga and replaced by the top two non-reserve teams from this division.