S.K. Omilabu, M.A. Ayo-Vaughan, D.C. Akintobi, I.T. Lawal, C.O.Alake G x environment interaction, additive main effect, stability, cowpea, seed yield 93-101 6 (4) 2022 October 2022 Grain yield and stability of yield performance of 26 cowpea genotypes was determined using AMMI model, GGE biplot analysis and the joint regression analysis of Eberhart and Russell for the interpretation of genotype x environment interaction. The results revealed significant (P≤0.01) genotype differences (2632.45) for all the characters evaluated suggesting genetic diversity among the cowpea genotypes studied. The AMMI and GGE-biplot analyses were found to be more efficient than the Eberhart and Russell analysis because the first two provided visual diagrams (biplots) in addition to the sum of squares. The first two interaction principal component axes of the GGE-biplot and AMMI models accounted for 79.4% and 75.1% of the total variation among the genotypes respectively. The GGE-biplot grouped the four environments into three mega-environments with Abeokuta-2 being the most representative and Igboora-2 the most discriminative environment. The GGE-biplots identified NG/SA/07/0113, NG/SA/07/0157 and NG/SA/07/0176 as the stable genotypes across the studied environments. The study concluded that NG/SA/07/0176 and NG/SA/07/0157 were stable across the environments as grouped by AMMI and GGE-biplot. These two genotypes with high yield and stability are recommended for cultivation.