Technical Abstract: Sweet potato is an important food crop in tropical and sub-tropical regions of the world. There is limited published research on yield stability of sweet potato in tropical environments. To identify cultivars with improved agronomic and stable yield characteristics, five elite cultivars obtained from the sweet potato breeding program in Uganda and International Potato Center (CIP) and five land race cultivars were evaluated for yield stability at 12 environments. The Additive Main Effects and Multiplicative Interaction (AMMI) model was used for stability analysis. The analysis of variance of yield data (t ha-1) for genotypes x locations, genotypes x seasons and locations x seasons was highly significant (P < 0.01) showing the variable response of the genotypes across environments and seasons. The average root yield of sweet potato cultivars were significantly (P < 0.01) greater at Kachwekano (KARDC) than at Namulonge (NAARI) and Serere (SAARI) locations. Based on AMMI statistical model, Araka Red and Tanzania were the most stable cultivars; while NASPOT 6 and NASPOT 2 had the lowest stability. The model predicted the highest yield from Dimbuca cultivar 4 of 12 environments and New Kawogo as the cultivar with the lowest yield in 6 of 12 environments. Within each environment and cropping season, the ranking of the cultivars for yield stability was not consistent. Selective deployment of cultivars across environments can improve sweet potato tuber yield in the lowland and highland tropics.