Mentoring is often recommended to universities as a way of supporting students with Autism Spectrum Disorders (ASD) and/or mental health conditions (MHC), but there is little literature on optimising this support. We used mixed-methods to evaluate mentees' and mentors' experiences of a specialist mentoring programme. Mentees experienced academic, social and emotional support, although subtle group differences emerged between students with ASD and MHC. The quality of the mentee-mentor relationship was especially important. Mentors also reported benefits. Thematic analysis identified that effective mentoring requires a tailored partnership, which involves a personal relationship, empowerment, and building bridges into the university experience. Mentoring can effectively support students with ASD and/or MHC, but this is highly dependent on the development of tailored mentee-mentor partnerships.