Zoonoses— infectious diseases transmitted between animals and humans—inflict a heavy toll on the economy, health, and livelihood worldwide. One Health serves as a framework to understand the interconnection of zoonoses risk factors and encourages collaboration, coordination, and communication among sectors. This dissertation examines the policy process and networks among the systems involved in preventing and controlling zoonoses in Peru. I applied a case study with rapid qualitative and systems thinking methods to analyze 75 semi-structured interviews and 77 network surveys collected among policymakers and experts of Peru's human, animal, and environmental national and subnational systems. Results offer a better understanding of the various zoonoses policy communities' belief systems that influence policy decisions and development and uncover implementation barriers for multisectoral activities at the subnational level.