Aluminum metal matrix composites are a class of advanced materials which have been developed for weight-critical applications in the aerospace and automotive industries. In the present investigation, tribological performance of aluminum micro- (100 to 200 μm particle size) and nano- (47 nm particle size) composites was studied using a three pin-on-disk apparatus under dry sliding conditions. As a basis for comparison, the tribological performance of aluminum alloys was also studied. The pins made of these materials were then slid against a steel disk under ambient conditions. Tests were conducted at a sliding velocity of 1.58 m/s for a normal load of 30 N. The worn surfaces of the pins and weardebris were analyzed using a scanning electron microscope. Based on the experiments, it was observed that the nano-composites significantly outperformed all of the other materials with respect to friction levels. It was also discovered that the nano-composites exhibited the best wear performance among the composites investigated. The size of the reinforcement particle trapped at the interface and the hardness of the mating materialwere specifically found to play an important role in determining the friction and wear behaviors of the materials investigated.