Summary The objective of the Supplement is to improve the assessment of mentoring, specifically in the NIGMS training programs, but also in other programs at the University of Georgia. Programs currently evaluate many aspects of their faculty, incoming students, curriculum, training objectives and student outcomes, but mentoring per se is not explicitly evaluated. Since the mentoring relationship is critical to the experiences of students, evaluating this relationship is especially important. Assessment of mentoring will allow students and faculty to gain insight into their mentoring performance relative to others, allowing them to modify practices or seek training. In addition, assessment allows general strengths and weaknesses to be identified at the program level and acted upon. To facilitate appropriate responses to assessment reports, the proposed work will also develop recommendations based on the assessment outcomes to be used by individuals and programs to improve their mentoring relationships. The overarching goal is to generate tools that allow mentoring assessment, generate actionable reports, and propose interventions that can be utilized iteratively, leading to long-term, sustained improvement of the mentoring relationships experienced by students in the NIGMS training programs and beyond. Such improvement will lead to better outcomes for students of all backgrounds.