The aim of the present article is to review literature on mentoring of school principals. The review focuses on the importance of mentoring in fostering effective leadership as a principal by presenting the pervasive definitions and perspectives on mentoring in the field. Second, based upon predefined selection criteria, we present empirical evidence from a number of studies organized by emergent themes on how mentoring in the principalship is conceived and valued. The bulk of the article presents evidence from studies organized along themes. Two central themes emerged in the review focused on determinants of effective mentoring relationships: a) the mentor and protégé pairing and b) length of time in the mentoring relationship including enough time for mentoring sessions. The article concludes with methodological recommendations and an outline of possible directions for future research concerning these commonly overlooked, yet critical features of successful mentoring programs