This study assesses the effects of periwinkle shell ash (PSA) on lime-stabilized lateritic soil. Preliminary tests were carried out on the natural soil sample for the purposes of identification and classification. The soil sample was classified as A-7-5. Thereafter, the soil sample was mixed with lime at percentages of 2, 4, 6, 8 and 10. These were later subjected to atterberg limit tests to get the optimum amount of lime, which was 10% because the least value of plasticity index was recorded at this state. PSA was added to the lime-treated soil sample at varying proportions of 2, 4, 6, 8 and 10%. The mixes were subjected to compaction, California bearing ratio (CBR), atterberg limits and unconfined compressive strength (UCS) tests, in so doing, the values of the CBR and UCS increased considerably. It can be concluded that the PSA performs satisfactorily as a cheap complement for lime in soil stabilization.Keywords: atterberg limits, lateritic soil, lime stabilization, periwinkle shell ash, soil stabilization