Today, practically every country’s system of administrative justice includes an administrative court reviewing for agency action. These courts settle a wide range of conflicts between governments and citizens, including very specialized issues such as antitrust, telecommunication, immigration, and human rights’ reparations cases. They have a broad impact, not only on citizens looking for redress against the government, but also on the implementation of public policy. However, minimal empirical scholarship has analyzed the origin, evolution, and performance of administrative courts. This thesis fills this gap by addressing the following questions in relation to administrative courts in Mexico: How are administrative courts created? Which political contexts determine the existence of such type of courts? How are they designed? How does this design affect administrative courts’ decisions? The researcher created a database encompassing the range of administrative courts in 31 states during 14 legislature periods, encompassing the political origin of each administrative court in Mexico, the specific design features of each, and trends in courts’ decisions. The analysis reveals a difference between the political origin of administrative courts and that of constitutional or general courts; posits how reformers might design rules that promote improvements of government performance through administrative courts; and presents evidence of the influence of design rules over administrative courts’ actual decisions.