This paper deals with professional teacher development. It specifically focuses on a research study of early childhood teachers' views and involvement in teaching music to young children. It presents findings from a comparative study of 38 teachers in three childcare centres in the Hong Kong Special Administrative Region and 24 teachers in four childcare centres in South Australia. Two research questions are discussed and answered: (1) What are early childhood teachers' levels of involvement in professional development in music? (2) Are there any significant relationships, that is differences and commonalities, in the findings between teachers' levels of involvement in these two cultural contexts? A unique research tool entitled Teachers' Music Development Scale was devised to collect data and measure teachers' involvement in music development. Specific findings and their implications are presented in the paper.