D uring the past two decades, considerable research has examined the impact of mentoring relationships at work (see Noe, Greenberger, & Wang, 2002; Wanberg, Welsh, & Hezlett, 2003, for recent reviews). A traditional mentoring relationship 1 is an intense interpersonal exchange between a senior, experienced, and knowledgeable employee (i.e., the mentor) who provides advice, counsel, feedback, and support related to career and personal development for a less experienced employee (the protégé) (Kram, 1985; Noe et al., 2002). A recent meta-analysis confirmed earlier qualitative reviews by finding that mentoring relationships are related to both objective and subjective measures of career success (Allen, Eby, Poteet, Lentz, & Lima, 2004). More specifically, mentored versus nonmentored individuals reported higher compensation, more promotions, and greater career satisfaction, career commitment, and job satisfaction (Allen et al., 2004). Although such evidence indicates mentoring relationships are beneficial for protégés, little research has investigated processes through which mentoring influences career success, and thus we know little about how mentors or protégés can influence the value of mentoring relationships (Day & Allen, 2004). We believe that individual differences, in particular personality characteristics, influence the effectiveness of mentoring relationships, and thus we discuss the role of personality in mentoring relationships.