Objective The aim of the present study was to investigate the extent to which initial levels and changes in ninth-grade adolescents' (n = 243) psychological well-being were associated with their school engagement after the transition to upper secondary education. In addition, we investigated whether a brief guided online acceptance and commitment therapy (ACT) intervention program delivered during ninth grade was associated with adolescents’ subsequent school engagement through changes in their psychological well-being.

Method Latent growth modeling (LGM) was used to examine the levels of and changes in well-being during ninth grade. Next, school engagement (measured by school satisfaction and dropout intentions) at the first year of upper secondary education was added to the model as a distal outcome variable. Finally, we examined the indirect effects of an online ACT intervention on subsequent school engagement through changes in psychological well-being. Effects of gender and academic achievement were controlled for in all analyses.

Results A higher level of life satisfaction at the beginning of ninth grade predicted higher engagement in upper secondary education, whereas increased depressive symptoms during ninth grade predicted lower engagement in upper secondary education. Also, participation in the brief guided online ACT intervention during ninth grade promoted school satisfaction through decreased depressive symptoms.

Conclusions The results suggested that psychological well-being and changes in psychological well-being during the final year of basic education are associated with school engagement after the transition to upper secondary education. The results also suggested that a brief guided online ACT intervention may increase psychological well-being, which can, in turn, support later school engagement.