This paper identified the dimensions of proactive socialization behavior among Chinese employees. We examined the mediating effects of perceived insider status on the relationships between proactive socialization behavior and socialization outcomes, and the moderating effect of supervisors' traditionality on the relationship between proactive socialization behavior and perceived insider status. Results from 280 newcomer–supervisor pairs supported the hypotheses that proactive socialization behavior was positively associated with task performance and social integration through perceived insider status. In addition, supervisors' traditionality significantly influenced the indirect relationships that proactive socialization behavior had with task performance and social integration via perceived insider status, such that the relationships became weaker as supervisors' traditionality increased. Copyright © 2013 John Wiley & Sons, Ltd.