Mentoring programs for youth have grown tremendously in popularity in recent years and in many important respects reflect core principles of community psychology. Mentoring of youth is a complex phenomenon, however, with a range of significant processes occurring at the levels of individual youth and their mentors, youth-mentor relationships and other interpersonal systems, programs, and the larger policy context. The research methods used to study youth mentoring need to be well suited to capturing this complexity. In this article, we argue, furthermore, that investigations of youth mentoring relationships and programs should be tailored to address concerns associated with each major phase of the intervention research cycle (i.e., preintervention, intervention, and preventive service systems research). Existing research pertinent to these differing phases frequently has not employed state-of-the-art methodology in the areas of sampling, design, assessment, and analysis. We also find that there are important gaps in the types of research conducted, and that in many instances, needed linkages across phases of the research cycle are lacking. Recommendations for strengthening future research on youth mentoring are discussed. (Contains 1 figure and 1 footnote.)