This study examined the lived experiences of seven beginning secondary mathematics teachers in an upper Midwestern state who had experienced mentoring and remained in teaching. The study sought to identify the mentoring experiences beginning secondary mathematics teachers perceive as most beneficial to their professional growth. Data were collected through individual interviews and focus groups and were analyzed by coding significant words and statements. Findings suggest beginning secondary mathematics teachers experience various types of support from assigned mentors and informal supports from colleagues within the same building. Regular observations with constructive feedback were found to be highly valued by beginning teachers.