Objective The aim of the present study was to examine the dyadic relationships between symptoms of anxiety and depression and life engagement in mother-adolescent and young adult (AYA) dyads with and without a history of cancer. Methods One hundred mother-AYA dyads and 50 mother-AYA cancer survivor dyads self-reported anxiety and depressive symptoms and life engagement. Multilevel modelling analyses were used to test actor–partner interdependence models. Results Significant actor effects of depressive symptoms on life engagement were found for AYAs and their mothers in both groups. But this effect was significantly attenuated downward in AYAs with a history of cancer. In addition, only AYAs' depressive symptoms exerted a significant effect on mothers' life engagement, indicating the presence of significant partner effects for mothers. Conclusion AYAs' and mothers' depressive symptoms are related to life engagement. Mothers' perception of depressive symptoms relates not only to their own perception of life engagement but also to that of their AYAs. These findings show the complex relationships that exist between AYAs and their mothers and point to the mechanisms through which AYAs-related variables affect mother outcomes, in the two groups of AYAs.