Abstract: This study investigated the effects of adding graphene nanoplates (GNPs) and carbon nanotubes (CNTs) into the Al7075 matrix via the stir casting method on the microstructure and mechanical properties of the fabricated composites. By increasing the volume fraction of reinforcements, the fraction of porosity increased. The X-ray diffraction results showed that the addition of reinforcements into the Al7075 changed the dominant crystal orientation from (002) to (111). Field emission scanning electron microscopy images also showed the distribution of clustered reinforcements in the matrix. Between the two reinforcements, the addition of CNTs generated a lower fraction of porosities. Through the addition of 0.52vol% GNPs into the matrix, the hardness, ultimate tensile strength and uniform elongation increased by 44%, 32%, and 180%, respectively. Meanwhile, the presence of 0.71vol% CNTs in the matrix increased the hardness, tensile strength and uniform elongation by 108%, 129%, and 260%, respectively.