PROmoting Geoscience Research, Education, and SuccesS (PROGRESS; progress.colostate.edu) is an NSF-supported mentoring program designed for undergraduate women interested in the earth and environmental sciences. Over the last decade, the program has served undergraduate women in the Colorado/Wyoming Front Range, the Carolinas, Texas, Georgia, California, and the DC/Baltimore corridor who attend a diversity of academic institutions. Based on longitudinal research, we know that participation in PROGRESS enhances students’ intention to persist in the earth and environmental sciences, increases science identity, strengthens their sense of belonging, and helps students develop strong and interconnected mentor networks. We will also share our latest results on effectively matching students with mentors. While there are many other mentoring programs that aim to support students navigating various challenges along their academic pathways in the geosciences, effectively matching students with mentors is often a challenge. PROGRESS has matched students with mentors based on needs, backgrounds, and interests and examined the longitudinal success of these relationships. We will share demographic, academic, and dispositional characteristics that should be considered when matching undergraduate students with mentors. Our research indicates that mentor-mentee relationships grounded in common undergraduate majors, gender identities, or current discipline are much more likely to be successful; these types of matching criteria can help students perceive the relevance of potential mentors. The practical lessons we have learned from PROGRESS can be adapted to other programs, such as those in the freshwater sciences interested in increasing retention of historically excluded groups in STEM.