This guidebook synthesizes lessons learned from the FAO Mitigation of Climate Change in Agriculture programme’s work with online communities of practice. It aims to help others searching for effective ways to organize and facilitate online communities. The guidebook is a one-stop resource bank and background for establishing an online community of practice. It is hoped that it will encourage practitioners to organize online learning events. The book is targeted at people working on knowledge management, participatory approaches, stakeholder consultations and networks to enhance online capacity development efforts. The guidance is valid for all sectors, but focuses on challenges related to natural resource management under climate change in the development context.