The objective of the present study was to examine the moderating role of interpersonal harmony in the relation of proactive personality with organizational citizenship behavior. 158 employees in Chinese state-owned companies completed the Proactive Personality Scale (Bateman & Crant, 1993), Harmony scale, and Organizational Citizenship Behavior Questionnaire. Proactive personality had insignificant correlation with job dedication. The correlation between interpersonal facilitation and proactive personality was significant but quite low. Results of the hierarchical regression analyses indicated that when demographic variables were controlled, Harmony had significant moderating effects on the relations of proactive behavior and job dedication/interpersonal facilitation. In the high Harmony group, the correlation between proactive personality and organizational citizenship behavior was significant; whereas in the low Harmony group, this correlation was not significant.