Adolescents' perceptions of their sibling relationship are important to their wellbeing, yet there is little work on the role of trust as a predictor of their adjustment. The present study investigated the effects of domain-specific facets of sibling trust on adolescent internalized adjustment. Participants included 169 early adolescents (51% girls) 10-13 years old with an older or younger sibling, who rated their perceptions of trust in that sibling and their depressed affect and intolerance of uncertainty across a 2-month period. Findings showed a positive association between reliability trust and honesty trust at T1. Results also indicated that reliability trust and honesty trust differentially moderated the stability of depressed affect. Specifically, higher levels of reliability trust attenuated the stability of depressed affect, whereas higher honesty trust appeared to strengthen it. Results emphasize the influence that sibling relationships, and trust between siblings, has on adolescent well-being. Findings are discussed in relation to theory and application to future interventions.