This handbook is a quick-reference tool that provides practical, field-level guidance to establish and maintain a GBV sub-cluster in a humanitarian emergency. It provides the foundations for coordination. More in-depth information can be pursued through resources referenced in this handbook. The GBV AoR website (gbvaor.net) maintains a repository of tools, training materials and resources that complement this handbook. As a second edition, this handbook provides updates to practitioners on humanitarian reforms, lessons learned, promising practices and resources that have emerged since its first publication in 2010.