This chapter examines a central moral problem arising in connection with the law on State responsibility: the problem of justifying the liability of ordinary State subjects for the material fulfilment of the remedial duties arising from their State’s wrongs. After isolating the problem and explaining its relationship to the question of whether States are moral agents, it critically examines a range of different justifications for subject liability, with a focus on theoretical justifications that have received less extensive attention in the literature. It considers: (1) causal contribution, (2) benefitting, (3) duties of aid, (4) part-constitution, (5) authorisation, (6) fictive authorisation, (7) moral vicarious liability, (8) duties to support valuable institutions and (9) lesser evil. The overall conclusion is that, even when State subjects are not morally responsible for the wrong which triggered a remedial duty, there are not infrequently moral liability justifications for State subjects bearing the costs of remedial duties. However, in practice, the imposition of subject liability is likely to be fully justified only on lesser evil grounds.