Many organizations are using knowledge management systems (KMSs) to facilitate knowledge sharing. However, few studies have empirically investigated how individual characteristics and organizational work practices influence knowledge sharing. Based on accountability theory, the person–situation interactional psychology perspective, and the five-factor model of personality, this study uses a quasi-experimental design to investigate how two accountability-inducing management practices—evaluation and evaluation plus reward—and their interactions with personality characteristics influence knowledge sharing using a KMS. One hundred employees from a Chinese software company participated in the study. The authors found that both evaluation and evaluation plus reward had a positive relationship with knowledge sharing. Greater levels of knowledge sharing occurred in the evaluation-plus-reward condition compared with the evaluation condition. Also, knowledge sharing was influenced by the interaction between evaluation plus reward and conscientiousness, neuroticism, and openness to experience. Implications of the study results for research and practice are discussed.