The purpose of this study was to examine the safety, feasibility, acceptability, and preliminary efficacy of a cross-age peer mentoring program created to improve adherence and psychosocial outcomes for pediatric liver transplant recipients. Twenty-two participants were assigned to a "mentor now" or "mentor later" waitlist control group. Tacrolimus SD, a validated measure of adherence, was assessed for six months pre- and post-intervention for both groups. Self-report measures of self-management and HRQOL were completed at recruitment and three months after training. Participant report indicated the acceptability of the intervention. Clinically significant improvement in adherence was detected. No significant changes on the psychosocial outcome measures at follow-up were observed. This study demonstrated that an outpatient-based mentoring program is a safe, feasible, and acceptable option to incorporate within a pediatric liver transplant program with potential for promising application in other transplantation populations as well. These results also suggest that the program may have been associated with meaningful improvement in adherence, although further evaluation is warranted.