This study examines the within and between sex differences on the relative importances of merchandise quality and interaction quality as drivers of behavioral loyalty (share of wallet). A sample of customers of a national retail chain serves as the study setting. The results indicate that for female customers, interaction quality and merchandise quality have equally strong total influence on share of wallet. For male customers, the total effect of merchandise quality on share of wallet is significantly stronger than the total effect of interaction quality. Across sex comparisons reveal that the total effect of interaction quality on share of wallet is stronger for female customers. However, merchandise quality exerts a stronger total influence on share of wallet for male customers. Implications of the results are discussed and avenues for future research are offered.