Community advocates for land rights justice in post-reformasi Indonesia frame their claims in terms of either indigenous (adat) rights or agrarian justice discourses. This study considers how these framings function, how effectively they support land rights struggles, and how they advance justice claims. The article provides analytical insights by comparing two conflicts involving communities and large-scale forest plantation companies in Sumatra. It finds that, where democratisation has opened up political space, agrarian justice framing provides a more effective basis for mobilising a wider coalition of actors in heterogeneous contexts and can provide political leverage in such conflicts. While recent changes have widened the legal space for indigenous (adat) rights within de jure 'state forests', the customary framing needs to fit community claims into the restricted, bureaucratised adat concept found in state laws and, in diverse rural contexts, may provide a limited vehicle for social mobilisation. Irrespective of the framing, unless effective mobilisation and legal reform can provide legal and political empowerment, political, institutional and structural barriers will continue to generate truncated agreements in conflict negotiations that potentially cement the exclusion and marginalisation of local communities from land access and control.