Single-layer space barrel vaults are appropriate structures for covering extensive spaces with large spans for which non-uniform support settlement is considered as a great concern. This can affect the stability and collapse behavior of these structures. Accordingly, in this paper, the collapse behavior of the barrel vaults with different slope angles is investigated under various types of the non-uniform support settlement. Both material and geometrical nonlinearity are taken into account while studying the effects of the settlements on the collapse progression in barrel vaults. Finally, the optimum slope angles of the structures are determined so that it minimizes the destructive effects of the support settlement. Moreover, the allowable values of the non-uniform support settlements provided by several code provisions have been investigated in detail.