Axiology is the philosophical discipline that studies questions of value. It is centrally concerned, then, with both the arts and with ethics and morality. Music teaching clearly involves questions of musical value and, because the wellbeing of students is at stake, teaching engages a wide range of ethical responsibilities. However, music education as an ethical endeavor is not typically emphasized in philosophies of music education, as part of music teacher training, in curriculum theory, or by accountability practices. There is, therefore, reason to think that music educators need to become far more aware of the ethical implications of their choices and actions. To that end, following a brief introduction to ethics, the author presents some ethical dimensions of teaching as a helping profession. Then the three major ethical theories are surveyed, with applications to school music. Following that survey, the author proposes a condition called "musicianism" to explain why music teachers can sometimes fail to meet important criteria of an applied ethics of teaching. In conclusion, a set of five principles for an applied ethics of school music teaching is recommended. (Contains 68 notes.)