New employees often learn an organization's unwritten rules— the "ropes"—through one-on-one relationships with workplace colleagues or mentors. Increasingly, organizations are implementing mentoring programs to foster supportive work relationships—and evaluators are being called on to assess them. This paper presents a systematic literature review of mentoringtype program evaluations and reveals wide gaps in what published studies report. The complex and long-term nature of mentoring programs presents unique challenges to evaluators. To meet these challenges we suggest an evaluation model that attends to local audience needs and addresses four evaluation stages: (1) context evaluation, for assessing needs, objectives and organizational support; (2) design evaluation, to assess mentor and protege characteristics, the process for pairing the mentor and protege, the program duration, activities and recognition/ rewards for participants; (3) implementation stage evaluation, to monitor activities, feedback and revisions; and (4) product evaluation, to assess systematically the planned and unplanned outcomes that consist of program reactions, learning, behavior change, and impact.