Mathematics specialist, mathematics teacher leader, teacher leadership, professional development, mathematics education, mathematics coaching What are the criteria for gaining access to a mathematics specialist (e.g., exemplar teacher, willingness of teacher, and teacher on probation)? Keywords: Mathematics specialist; mathematics teacher leader; teacher leadership; mathematics coaching; professional development; mathematics education EN Mathematics specialist mathematics teacher leader teacher leadership mathematics coaching professional development mathematics education 1 10 10 04/11/23 20230101 NES 230101 Introduction The need for mathematics specialists has been well documented (e.g., Association of Mathematics Teacher Educators, [1]; Dossey, [18]; Fennell, [22]; Gojak, [29]; Lott, [40]; National Council of Teachers of Mathematics, [46]; Nickerson, [51]/2010). Extending the research on individual coach-teacher interactions via coaching cycles, Gibbons and Okun's ([25]) research examines a mathematics specialist (i.e., coach) and classroom teachers' interactions with students.