This study explored the effect of tertiary teachers' goal orientations for teaching on their commitment, with a particular focus on the mediating role of teacher engagement. The results of a survey of 597 Chinese tertiary teachers indicated that teacher commitment was positively predicted by ability approach, mastery and relational goals, but was negatively predicted by work avoidance goals. Ability avoidance goals positively predicted teacher commitment to institution and to students, but negatively predicted teacher commitment to profession. Moreover, teacher engagement mediated the effect of ability approach, mastery and work avoidance goals on teacher commitment. The mediation effect of teacher engagement between teachers' ability avoidance and relational goals and teacher commitment was not significant. The results of this study have implications for understanding the nature of teachers' psychological state and attitudes towards teaching and for the enhancement of teacher commitment.