Mentoring is a common practice in higher education institutions and scientific fields. Undergraduates approach faculty members who are working on topics that match their research interests. We conducted a study to compile a qualitative synthesis of research on the mentorship experience of undergraduate science students with faculty mentors. We used the stages of meta-ethnography to guide our study. Meta-ethnography involves identifying concepts from qualitative studies to translate them into a line of argument. We screened 2,888 titles and abstracts, 71 full texts, and included 13 studies in the synthesis. We identified and organized nine conceptual categories into two themes: student success and engagement, and barriers to student progression. The findings show that faculty mentorship is key to supporting student retention and increasing the scientific pipeline.