Purpose: The purpose of this paper is to examine the critical success factor of tacit knowledge-sharing behavior among the academic staff of higher learning institutions. Design/methodology/approach: A total of 200 questionnaires were distributed among the academic staff of higher learning institutions in Bangladesh. Collectively, 150 usable responses were returned. Apart from descriptive statistics, this research applied confirmatory factor analysis (CFA) and structural equation modeling (SEM) to assess the measurement model and test the research hypotheses. Findings: The findings from this empirical examination show that all the Big Five personality traits affect tacit knowledge-sharing behavior among the academic staff of higher learning institutions, except conscientiousness personality trait. However, the role of motivation, self-efficacy and mutual trust are also playing a significant role in tacit knowledge-sharing behavior. The CFA, SEM analysis confirmed the proposed conceptual model with a good model fit. Research limitations/implications: The findings of this research contribute to the understanding of the role of personality traits and other antecedents which play a significant role for the academic staff tacit knowledge-sharing behavior which are interesting for policymakers and authorities of higher learning institutions. As there was no sampling frame, the researchers applied convenient sampling technique in choosing the respondents. Originality/value: This research plays a pioneering role where it contributes to the growing literature on the relationships between personality traits and other factors to construct a model for the tacit knowledge behavior by considering academic staff of higher learning institutions from a developing country's perspective.