Scholars of decades past, current researchers, and various reform documents all deal, directly or indirectly, with the question of what constitutes good mathematics teaching. Often good teaching is situated in the context of broader educational goals, such as preparing literate citizenry. Researchers generally define good teaching implicitly with attention to various processes such as reasoning and problem solving. In a series of three interviews, we examined nine experienced and professionally active teachers' views of good mathematics teaching and how it develops. The interviews were couched in the context of the teachers mentoring student teachers. In general, these teachers thought good teaching requires a sound knowledge of mathematics, promotes mathematical understanding, engages and motivates students, and requires effective management skills. Furthermore, the teachers felt that good teaching is developed from experience, education, personal reading and reflection, and interaction with colleagues. Experience was considered the primary contributor. The article compares and contrasts the teachers' notions of good teaching with those of various scholars and researchers and positions stated in various reform documents.