Metal matrix composites have better mechanical and tribological properties compared to the matrix materials.This study presents effect of heat-treatment on hardness and tribological properties of A356 aluminum alloy reinforced with different weight fractions of Al₂O₃ particles. Metal matrix composites were fabricated by stir casting method. The sliding wear test was carried using Pin-on-Disc apparatus at a constant sliding speed of 1m/s and load of 30 N. Wear resistance of A356 alloy and its composites was improved after heat treatment with improving ratio between 14-17.3% as compared to as cast conditions. The heat treated test specimens also resulted in marked improvements in hardness as compared with these materials in the as-cast condition.