Mathematics coaching, which can be defined broadly as job-embedded learning for mathematics teachers with someone who can help, is being used in Canada to improve teaching practice and increase student achievement. Mathematics coaching research is quite new with little written on the components of effective coaching. The paper attempts to contribute to this research. Employing observations, interviews, archival data, and surveys, the study finds that time, trust, the coaches' backgrounds, and their courage in trying new initiatives may be elements of effective coaching. Effective coaching also required resources and was differentiated. Mathematics coaching improved teacher practices.