This chapter presents an overview of the use of proportionality in the case law of the Mexican Supreme Court, which has used it mainly to analyze human rights restrictions established by the legislator in statutes. The study identifies two periods. In the first period, the Court begins to use proportionality to analyze the constitutionality of legislative classifications that allegedly violated the right to equality, under a syncretic methodology that is applied not always consistently. More recently, the test has been used more often and regarding rights of very different types, providing a crucial support to the enforcement of the 2011 human rights’ constitutional amendments. The chapter documents the reception of proportionality in terms of both substance and methodology but also offers insight on the main difficulties experienced along the process and on the challenges its use in the Mexican judiciary poses for the future.