Mutation breeding is a promising technique used for improving crop plants' performance, including tolerance to aluminum in rice (Oryza sativa L.) cultivars. The presented research pursued developing aluminum-tolerant rice lines through mutation in two local rice cultivars, 'Mayas' and 'Adan'. Mutation induction using six doses of gamma irradiation included 50, 100, 150, 200, 250, and 300 Gy. The evaluation of root tolerance index proceeded for early selection of aluminum tolerant lines. In addition, root swelling, aluminum absorption, cross-sectional histology, and root lipid peroxidation incurred scrutiny. The results showed gamma irradiation (100 Gy) could produce aluminum stress tolerant lines from the cultivar Mayas. Aluminum-tolerant lines obtained totaled 91 through gamma irradiation in the local rice genotypes. The morphological traits of these aluminum-tolerant mutant lines underwent accumulation only at the root tip, cross-sectional histology with sclerenchyma thickening due to organic acids, and minimal cell wall damage. These lines need further evaluation to confirm their tolerance to aluminum stress, for rice cultivation on acid soils.