Sesame (Sesamum indicum L.) is the queen of oil crops grown globally due to its nutritional, industrial and economical values.To increase sesame productivity in our country improved variety is a mandate for plant breeder.The present study was conducted to assess the genetic variability and association of traits in 64 sesame genotypes for seed yield and related traits in Assosa, Western Ethiopia during the 2021 main cropping season using 8x8 simple lattice design based on 22 (7 qualitative and 15 quantitative) traits. ANOVA indicates a highly significant (P<0.001) difference among genotypes for all quantitative traits except internode length and number of secondary branch, indicating the existence of genetic variability. High PCV, GCV, H 2 bs(%),GAM were recorded for height to first capsule, number of primary branches per plant, number of capsules per plant,indicates a lesser influence of environment in the expression of these traits selection possible. Seed yield had highly significant positive correlations with all qantitative traits except intenode length and capsule length and negative correlations with bacterial blight severity. Number of capsules per plant ,days to maturity and seed yield per plant showed high direct contribution on seed yield and those trait also effects on oil content ethier direct or indirect ,indicates the improvenet in seed yield based on those trait simlitanous improve oil content . Cluster analysis grouped sesame genotypes into four clusters and revealed the presence of genetic divergence and the maximum inter-cluster distance was obtained between cluster II and cluster IV (D 2 =76.00) which can bring maximum heterosis in sesame. principal component analysis, 71.8% total variation among genotypes was explained by the first three principal components . The estimated Shannon diversity index showed relatively polymorphic variation for capsule beak (0.57) followed by branching pattern (0.51), number of carpels per capsule and the number of locules per capsule (0.14) The present study confirmed the variability among genotypes therefore, promising genotypes and determinant traits should be considered for future sesame improvement.