This chapter illuminates the different paths that the concepts of jurisdiction and admissibility have taken in the Appeal Chamber’s jurisprudence at the International Criminal Court. It observes that appeals on jurisdiction have been rare although some jurisprudence is discussed and that the admissibility of cases is a recurring issue. Further, the latter topic has heralded some of the most influential judgments to date. This chapter argues that the Appeals Chamber has declined to take an activist approach and carefully delineated the scope of judicial responsibility for complementarity when assessing admissibility. In relation to admissibility, three generations of admissibility litigation are briefly described (categorised by the time periods of pre-2009, September 2009 – 2010 and March 2011 until today, respectively), exploring questions such as when a case is already being investigated or prosecuted by a State or when a State is unwilling or unable to investigate or prosecute, inter alia. The procedures for reviewing or challenging admissibility are also analysed.