Previous research has shown that disasters often involve a sense of injustice among affected communities. But the empowerment process through which ‘disaster communities’ organise strategically to confront such injustices have not been investigated by social psychology. This study addresses this gap by examining how community members impacted by the Grenfell Tower fire self-organized to demand justice in response to government neglect. Thematic analysis of interviews with fifteen campaigners helped us to understand the strategies of those involved in support campaigns following the fire. Campaigners aimed to: overcome injustice against the government inactions in the aftermath of the fire; empower their community against government neglect; create a sense of community for people who experienced injustice. Community members created a petition calling on the government to build trust in the public inquiry; they achieved their goals with the participation of people from wider communities. We found that reaching out to allies from different communities and building shared social identity among supporters were two main ways to achieve campaign goals. The study suggests ways that empowerment and hence organizing for justice can be achieved after a disaster if campaigners adopt strategies for empowering collective action.