As part of the centennial celebration for the Journal of Applied Psychology, this article reviews the literature on organizational socialization and mentoring. Our review includes a comparison of organizational socialization and mentoring as processes for employee adjustment and development, the historical context that fueled the emergence of these two areas of study, and a chronological mapping of key foundations, trends, themes that emerged across time, and major milestones. Along the way, a special emphasis is placed on research published in the Journal of Applied Psychology and high impact work is highlighted. We conclude with a discussion of five areas for future research. Specifically, we outline ideas for bridging the socialization and mentoring literatures, better understanding and capturing dynamic processes across time, the development of multilevel theories and models, addressing causality, and considering the implications for organizational socialization and mentoring research based on how technology is changing the way we work.