TiC reinforced AZ91 magnesium matrix composites have been fabricated by a melt in situ reaction spray deposition. The microstructures of spray-deposited alloys were studied by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The dry sliding wear behavior of the alloys was investigated by using a pin-ondisc machine under five loads, namely 10, 20, 30, 40, and 50 N. The composites had much better wear-resistance than the matrix alloy. The wear behavior of the composites was dependent on the TiC content in the microstructure and the applied load. The improvement in the wear resistance of the composites became more prominent at larger normal load. At a lower load (10 N), with increasing TiC content, the wear rate of the composite was decreased, and the dominant wear mechanism was an oxidative mechanism. At a higher loads (50 N), a spray-deposited AZ91/TiC composites exhibited superior wear resistance to the AZ91 magnesium alloy, and the dominant wear mechanism was delamination.