The international legal mechanisms to invalidate patents continue to expand. While some countries require all validity challenges to be conducted in ordinary civil courts, most countries now have available a variety of administrative procedures or specialized tribunals to address patent validity. These administrative proceedings can have a profound impact on not only patent validity but on the way proceedings flow and are managed in the civil courts. In some systems, such as the U.S.A., patent validity can be challenged administratively within the Patent Office in an inter partes review, post-grant review, or ex parte reexamination proceeding. Europe offers not only a wide variety of countries and legal systems but there is the concurrent opportunity to be involved in an EPO opposition proceeding. Thus, administrative and specialized tribunal invalidity challenges can take many forms, and the strategy taken during administrative proceedings can be dependent on the options and timing of the civil courts. The variety of non-judicial proceedings can occur in many jurisdictions and each offers its own set of advantages.