This thesis proposes to examine the law of jurisdiction to render provisional and protective measures in transnational commercial disputes in order to identify the main problems that arise in each dispute resolution system. Legal scholarship in this area is extensive, albeit fragmented and chaotic. Academic commentators have immersed themselves in the undertaking to examine the authority of courts and arbitral bodies to render interim measures without proper insight or analysis of basic concepts of the law of jurisdiction such as adjudicatory jurisdiction, competence, and procedural powers. Furthermore, the traditional divide between litigation and arbitration appears to have prevented a comprehensive analysis of jurisdictional aspects in the specialist area of interlocutory relief. This chaotic scenario has also reached national courts and arbitral bodies which, in practice, have not properly categorised these jurisdictional issues. Against this background, the thesis: i) conducts a comprehensive analysis of the two adjudicatory methods of dispute resolution - litigation and arbitration -, ii) is based on a detailed examination of the relevant concepts of the law of jurisdiction that come into contact in the law and practice of interim measures, and iii) conducts a practice-focused analysis with reference to published decisions in order to discern how courts and arbitral bodies address, in practice, the issue of their jurisdiction and competence to render interim relief. Once the relevant legal sources are gathered and the law of jurisdiction is comprehensively analysed, the thesis identifies the main problems that arise in each dispute resolution system. The analysis of these problems leads to two significant conclusions. First, the distinction between jurisdiction and competence is important since these concepts have different legal implications in the practice of provisional measures. Secondly, a closer dialogue is needed between international commercial arbitration and private international law. International arbitration did not reinvent jurisdictional concepts; however, the notion of jurisdiction as understood in private international law has not been always applied in the arbitration setting. Indeed, in some instances, the jurisdictional decisions of arbitral tribunals and emergency arbitrators in the area of provisional measures have not rested on proper juridical concepts and legal principles. The adoption, in arbitration, of the vertical paradigm of jurisdiction as applied in private international law would have prevented unfortunate arbitral decisions. Furthermore, from a doctrinal point of view, the application of this jurisdictional paradigm can be based on the fact that international arbitration predominantly operates within private international law. Based on the above-mentioned conclusions, this thesis proposes different recommendations to the actors involved in each dispute resolution system, that is, litigation and arbitration users, law and policymakers, and the adjudicatory bodies involved. The purpose of these recommendations is to facilitate the future work of courts and arbitral bodies and to offer some degree of predictability to litigants and arbitration users. In particular, the thesis recommends the following. As regards international litigation, the thesis concludes that one of the main developments in the area, Article 35 of the Brussels I Recast, is founded on the principle of open jurisdiction. Jurisdictional norms based on the notion of open jurisdiction create more problems than they solve, particularly, if their purpose is legal harmonisation or unification. Accordingly, a clear rule of jurisdiction based on proper connecting factors should be adopted instead. Furthermore, the thesis recommends that national courts should avoid adopting a differential treatment between arbitration and litigation when it comes to judicial support since the connecting factors adopted by each dispute resolution system are fundamentally the same. As regards international arbitration, the thesis identifies an important problem in the context of the assessment of prima facie jurisdiction conducted by arbitral tribunals. The thesis then demonstrates that the concept of prima facie jurisdiction should include the issue of whether the parties have consented to arbitrate. Lastly, the relatively recent institution of emergency arbitration is examined. After concluding that there are no legal impediments that would advise against the implementation of the jurisdictional role of emergency arbitrators, the thesis recommends lawmakers to embrace the development first adopted in Singapore which equates the powers of tribunals and emergency arbitrators albeit, of course, restricted to the pre-arbitral stage.