A great deal of attention is now paid to the ethics of social research. Research governance has expanded, and a burgeoning literature is emerging that describes the processes, practices and questions that arise in social research with children, families and communities. This paper outlines the approach taken to research ethics within Young Lives, a long-term study of childhood poverty in four developing countries. It describes some of the practical difficulties that Young Lives faces, and emphasises the importance of understanding local contexts in undertaking research with children and families in environments that are dynamic and may change rapidly from one year to the next, economically, environmentally and politically. The paper aims to contribute to current debates about research practices, the ethics of longitudinal research with children and research with communities in majority world contexts, in the spirit of shared enquiry and learning.