This chapter explores the interaction between international human rights law (IHRL) and international humanitarian law (IHL), as well as international criminal law. It examines how IHRL influences the application and development of IHL and how human rights principles are integrated into international criminal procedures and substantive law. The chapter discusses the mutual reinforcement and potential conflicts between these branches of international law, highlighting the need for a coherent and integrated approach. It also explores the role of international courts and tribunals in applying and interpreting IHRL, IHL, and international criminal law, and the challenges in ensuring compliance and accountability.