The Best Practice Guide is operational guidance on how to set up and run an inter-agency community-based complaint mechanism (CBCM) to handle reports of sexual abuse and exploitation by aid workers. It compiles lessons learned, examples, and case studies gathered throughout the course of a 2013–2015 pilot project on inter-agency CBCMs, which IOM coordinated on behalf of the Inter-Agency Standing Committee (IASC). The Guide is an easy-to-use living document that offers practical guidance, and includes global Standard Operating Procedures (SOPs) on inter-agency cooperation in complaint handling. With the endorsement of the IASC Principals in June 2016, it addresses a gap for high-level PSEA guidance transmitted to our representatives in the field. For more information about inter-agency PSEA initiatives, or to receive a hard copy of the Guide in English, please contact PSEA-CBCM@iom.int or helpdesk-aap-psea@unhcr.org.