This chapter seeks to provide clarity with respect to certain legal questions that have recently emerged in connection with the provisional application of the EU’s mixed trade and investment agreements. Thus, the EU may only provisionally apply those parts of a mixed agreement falling within the scope of its competences. A Member State’s notification to the other parties to the agreement of its refusal or failure to ratify the agreement does not preclude, as a matter of international law, the provisional application of the agreement by the EU; nor can Member States unilaterally terminate such provisional application. In order to discontinue the EU’s provisional application of a mixed agreement, an act of the EU itself is needed. However, an argument can be made that where a Member State permanently and definitively fails to ratify a mixed agreement, the EU is under an obligation, as a matter of EU law, to terminate the provisional application of that agreement.