Motivation, an inner state that incites an individual to specific behaviours, has been recognized early in the aspect of work and career development. In the educational context, achievement goal orientations are one of the key cognitive factors of motivation. They reflect the reasons why an individual is trying to succeed on a particular task. Given the important outcomes of beforementioned orientations that include both intentions and concrete behaviours, there are indications that goal orientations also affect attitudes toward work, such as work engagement and commitment. Therefore, the aim of this research is to examine the relationship between teachers' achievement goal orientations and teacher commitment, and the mediating role of work engagement on this association. 299 teachers employed in primary and secondary schools in the Republic of Croatia participated in an online study. The expected positive correlation between the mastery goal orientation and commitment and the negative correlation between the work avoidance goal and commitment were confirmed. Teachers who have more pronounced mastery goals, but also those with less pronounced work avoidance goals, show higher commitment. Furthermore, work engagement completely mediated the effects of mastery and work avoidance goals on teacher commitment. The implications of these results speak in favour of understanding the importance of more detailed research of teachers' attitudes towards work in order to be able to devise strategies to develop the Croatian educational system, and increase the satisfaction of teachers.