A line x tester analysis using nine lines and five testers was carried out to study the combining ability and gene action in sesame for seed yield and its related 11 quantitative traits. The partitioning of variances due to the crosses showed that the mean squares due to lines were found significant for all the characters except for number of branches per plant and oil content, whereas mean squares due to testers and lines x testers were found significant for all the characters except for the plant height and number of branches per plant. General and specific combining ability variances showed the involvement of both type of gene actions in the inheritance of these characters. Among the parents, two lines viz., AT-472 and AT-483 and three testers viz., GT-2, GT-3 and GT-6 exhibited good general combining ability effect for seed yield per plant. The cross combination, AT-471 x GT-2 showed significant and positive sca effect for seed yield per plant and involved average x good combining parents. It was followed by AT-464 x GT-4 and AT-472 x GT-3 which involved either good x good or poor x poor combining parents. These crosses have been identified as best hybrids for improving seed yield per plant.