Due to abundant frequency resources, millimeter wave (mmWave) spectrum draws much attention as a solution to bandwidth scarcity. However, characteristics of mmWave transmissions, such as blockage and reduced coverage, make conventional network architectures inefficient for use in mmWave communications. A recently proposed multi-tier mmWave network architecture allows for relaying around blockages and enlarges the coverage of each Backhaul at an acceptable deployment cost. Nevertheless, this architecture introduces major challenges to scheduling. The necessity of both enabling flexible user association and fully exploiting wireless Backhaul requires cross-tier consideration of multi-tier mmWave networks. This thesis comprehensively analyzes the scheduling of downlink multi-tier mmWave networks by jointly regulating transmissions in all tiers. The cross-tier optimization problem is NP-hard, but a sub-optimal scheme which iteratively optimizes schedules of different network tiers is proposed with polynomial computational complexity. Simulations show that our algorithm significantly outperforms benchmarks in spectral efficiency and fairness with various user distributions.