As large expenditures are made every year to support the professional learning of teachers, it is critical to know if these endeavors are effective. Mathematics coaching has become an avenue that is believed to be an effective form of professional development in supporting mathematics teachers in their own improvement of teaching mathematics. However, it is unknown, particularly at the secondary level, whether or not mathematics coaching holds the same promise as it does in other subject areas or grade levels. The purpose of this qualitative phenomenological study was to explore the experiences of secondary mathematics teachers who have worked with a mathematics coach. The three research questions that guided this exploration were (1) what are the experiences of secondary mathematics teachers working with a coach, (2) what are the secondary mathematics teachers’ perceptions of the role of a coach, and (3) in what ways do secondary mathematics teachers feel they have changed as a result of working with a coach? Fifty-six secondary mathematics teachers from across the United States responded to a survey containing both closed- and open-ended questions about their coaching experience. Four of these participants were questioned further through the use of a semi-structured interview. Results indicated that almost 70% of the participants indicated that coaching was either very beneficial or somewhat beneficial. Meaningful elements of the coaching experience included the knowledge of the coach, the availability of the coach, the relevance of the content of the coaching interactions, the teacher-coach relationship, and exposure to new ideas. Furthermore, interviews revealed that participants didn’t always understand the role or purpose of the coach. Finally, participants indicated changes in a variety of areas such as curriculum, instructional strategies, planning, and confidence. These findings provide support for mathematics coaching at the secondary level as a form of effective professional learning for most participants.