Concepts of justice are now routinely mobilised in environmental and climate change activism. Within the climate change arena, issues of justice have come to the forefront through international negotiations and concerns around rights and responsibilities, while environmental justice activism has sought to consider both distributional and procedural issues. More recently, the concept of energy justice has gained prominence, most frequently framed in terms of access to affordable energy and fuel poverty but also related to the politics of energy infrastructures. To date however, there has been little critical interrogation of the concept of energy justice in relation to actions undertaken by activist and advocacy movements. Drawing on empirical work with NGOs, this paper explores two interrelated questions. First it seeks to analyse the existence and utility of energy justice as an activist frame and secondly, to draw out the connections with climate and environmental justice activism. Understanding these interconnections, both in discourse and practice, will allow a more nuanced understanding of justice in the wider context of a low carbon transition.