Leveraging the motivation-opportunity-ability (MOA) theoretical framework and past research on psychological climate, this study analyzes three antecedent factors driving an individual's knowledge-sharing (KS) within organizations: knowledge-sharing psychological climate as motivation, information management capability as ability, and organizational information technology support as opportunity. An empirical examination reveals that a motivating psychological climate has a primary impact on KS behavior, and the impact of perceived information management capability on sharing is mediated by the psychological climate. Perceived organizational use of information technology to support knowledge work bears strong influence on information management capabilities but not on sharing, suggesting that investment in IT does have indirect payoffs. The study is the first to position the opportunity→ability→motivation causal network in an individual's KS behavior. The findings suggest that managers need to consider the pre-requisite roles of IT-enabled opportunities and workers' information management abilities when building an all-important motivating climate to share.