The current study aimed to explore the concept of transition self-efficacy, which is defined as individuals' subjective evaluation of their ability to execute the actions required for a successful transition from elementary to middle school. The study followed a sample of 128 sixth-grade students for 2 consecutive years (before and after the school transition). A path analysis based on structural equation modelling revealed that the students' perceptions of the teachers' emphasis on mastery goal orientations predicted academic and social aspects of self-efficacy. The social aspect of self-efficacy in turn predicted changes in the students' emotional and behavioural engagement after the transition. The results were robust when we controlled for self-reported GPA and gender. An interaction between gender and aspects of self-efficacy was also observed. The findings emphasise the importance of transition self-efficacy for adaptive school transitions and provide evidence that teachers' goal emphases play a significant role in promoting self-efficacy.