Cassava (Manihot esculenta Crantz) is an important root and tuber crop worldwide. The crop is highly influenced by variations in production environments. A significant Genotype × Environment Interaction (GEI) presents challenges in the selection of superior genotypes. This study determined the magnitude of GEI and stability performances of 26 cassava genotypes for key agronomic traits across three multi-environments. The trial was laid out in a randomized complete block design during 2016/2017 cropping season. Genotype TR0288 had the highest starch content at Pendembu and Kambia, while TR1436 performed best at Njala. Genotype TR0768 had the highest fresh storage root yield at Pendembu, TR0455 at Kambia and TR0591 and TR0657 at Njala environments. For dry matter content, genotypes SLICASS4, TR0310 and TR0740 performed best at Njala, Pendembu and Njala, respectively. Genotype TR0455 had the highest fresh storage root yield across the three production environments, TR1436 for starch content and TR0310 for dry matter content. TR0310 was the most stable and favorable genotype based on mean dry matter content and stability performance across the three production environments. Harvest index was positive and significantly correlated with storage root (r = 0.54***), fresh storage root yield was highly and positively correlated with number of storage root (r = 0.61***) and harvest index (r =0.49***). The information generated is relevant for selection initiatives targeted at superior high yielding, high dry matter content and starch content cassava genotypes combining resistance to cassava mosaic in Sierra Leone.