Mentoring between psychology undergraduate students and A-level psychology pupils, from widening participation (WP) backgrounds, was run as action research over four academic years. The key aims were to support potential new university students' transition into higher education (HE) and current students' transition out of HE into work or further study. Benefits included significant increases in mentors' employability skills and career-related goal achievement, reported gains for mentees in insight into going to university, knowledge of psychology, and academic skills, and links between the university and local schools. Challenges included difficulties in scheduling, the time demands involved, keeping the opportunity accessible, and working effectively with student mentors and RAs. University-school mentoring can effectively support undergraduates' employability whilst benefitting potential new students, but having more than one coordinator is recommended.