IntroductionAdolescents often face challenges in maintaining their wellbeing during adolescence. While numerous support services are available, their referral systems depend on adolescent self-reports or proxy referrals using ambiguous behavioural cues. ObjectivesThis review examines the alignment between proxy reports and self-reports of adolescent wellbeing, aiming to identify predictors of closely matched reports in non-clinical adolescent populations. Further, the review aims to identify variables that predict closely matched reports to determine the characteristics of a more accurate proxy assessor of adolescent wellbeing. MethodsA systematic literature search was conducted in September 2021 following PRISMA guidelines. Four databases (Scopus, PsycINFO, Medline, and Ebscohost) were searched for studies assessing wellbeing or related constructs in non-clinical adolescents aged 12 to 18. Studies in which there were both self-report and a proxy report, and that assessed concordance between the two reporters were included. ResultsTwenty-one studies met inclusion criteria, showing moderate concordance between parents and adolescents, with less agreement between teachers and adolescents. However, there were few teacher-adolescent studies. The findings indicated that predictors of concordance are more likely to be relationship factors, such as communication, closeness and warmth, rather than age, gender, or proxy role. Patterns emerged that indicate mothers’ reports of adolescent wellbeing, as compared to fathers was more closely matched to adolescent self-reports on psychological and emotional domains. ConclusionAdolescents’ reluctance to report wellbeing concerns necessitate proxy measures for identifying support needs. However, discrepancies between parent proxy reports and adolescents' self-reports warrant further research to establish reliable use in referrals. Additional investigations are needed to determine characteristics of a valid proxy reporter, focusing on relationship factors such closeness, warmth, communication, and time spent together. Moreover, teacher-adolescent concordance research is lacking and warrants attention. This systematic review failed to identify sufficient studies to conduct a meta-analysis. In addition to more studies on teacher-adolescent concordance, and more detailed investigation of predictor variables including age, we strongly encourage researchers to report more detail in their analyses, allowing the field to develop a stronger body of evidence.