The International Criminal Court (ICC) was established with the aim of prosecuting individuals for the gravest crimes of concern to the international community. Yet some provisions of its Statute (the Rome Statute) recognize the need for temporarily setting aside criminal investigations or prosecutions in favour of different considerations. Two of these provisions are Article 53(1)(c) and (2)(c) of the Statute. They allow the Prosecutor of the Court to use his or her discretion in deciding not to initiate an investigation or a prosecution in the ‘interests of justice’. Nonetheless, the ambiguity of this phrase, coupled with an absent definition, have given rise to a polarized debate about its meaning and the Prosecutor's ensuing margin of discretion: some consider matters of peace and security and alternative justice mechanisms as possible ‘interests of justice’, while others exclude them. Among those adopting the latter view is the ICC's Office of the Prosecutor (OTP), as can be inferred from a 2007 Policy Paper on the Interests of Justice and a 2013 Policy Paper on Preliminary Examinations, which continue to be upheld by the Office. Against this backdrop and amid new developments at the ICC which call into question the OTP's position, the purpose of this article is to develop a comprehensive interpretation of Article 53(1)(c) and (2)(c) of the Rome Statute, using all the interpretative tools provided by Articles 31 to 33 of the Vienna Convention on the Law of Treaties.