Owing to the recent advances of non-orthogonal multiple access (NOMA) and millimeter-wave (mmWave),these two technologies are combined in unmanned aerial vehicle (UAV) networks in this paper.However,energy efficiency has become a significant metric for UAVs owning to their limited energy.Thus,we aim to maximize the energy efficiency for mmWave-enabled NOMA-UAV networks by optimizing the UAV placement,hybrid precoding and power allocation.However,the optimization problem is complicated and intractable,which is decomposed into several sub-problems.First,we solve the UAV placement problem by approximating it into a convex one.Then,the hybrid precoding with user clustering is performed to better reap the multi-antenna gain.Particularly,three schemes are proposed,where the cluster head selection algorithm is adopted while considering different equivalent channels of users.Finally,the power allocation is optimized to maximize the energy efficiency,which is converted to convex and solved via an iterative algorithm.Simulation results are provided to evaluate the performance of the proposed schemes.