The rise in surface transport by wheelchair users raises significant safety considerations. In particular rear impact injuries have not been adequately addressed. In this paper, rear impact crash simulations of a wheelchair occupant with scoliosis have been used to quantify the influence of scoliosis on spinal loading. The results show an increase in effective sagittal plane stiffness introduced by the curvature of the scoliosis, which results in increased spinal loading. Furthermore, the complexity of the deformed spinal curves means that the commonly used Cobb angle classification is not an appropriate means of assessing wheelchair user spinal loading during impact.