Members of the public and resource-dependent communities are increasingly participating alongside professional scientists to monitor the natural world. This study applies the contention from development studies that participatory approaches may be tyrannical to participatory monitoring of Nepal's community forests. There is a tyranny of the group because elites within the community stand to benefit at the cost of those already marginalized. In theory, tyranny is produced through the methods employed in the projects, as they promote scientific systems of monitoring at the expense of local understandings of environmental change; in practice, however, the latter aspects override official monitoring to enable effective learning from the projects. In some instances, tyranny is produced through decision-making and control, whilst, in other cases, the reverse is true and communities are empowered through their participatory monitoring efforts. Policy makers and those involved in participatory monitoring should endeavour to transform tyranny created at local and wider scales. Participatory monitoring holds huge potential in the assessment of biodiversity, natural resources and ecosystem services, but programmes and projects need to effectively deliver associated benefits of conservation and community empowerment.