BackgroundEating disorders (EDs) are severe mental illnesses with high rates of mortality, morbidity, and reduced quality of life. Their onset occurs during adolescence and early adulthood, coinciding with the critical transition from pediatric to adult care. To address the lack of guidelines to support ED transitions in Canada, this study developed evidence-based guideline recommendations.MethodsScoping review methodology was employed using comprehensive searches across seven databases, supplemented by forward and backward citation chaining to identify records on youth and young adults (YYAs) (16–25 years) with EDs and/or mental health conditions transitioning from pediatric to adult care. The Grading of Recommendations Assessment, Development, and Evaluation approach was used to evaluate the quality of the evidence for applicable studies. Using a modified Delphi method, the evidence was reviewed by a guideline development panel and consensus was achieved in a single round of voting.ResultsAfter de-duplication, 14,350 records from all sources were screened, with 1817 studies undergoing full-text review. A total of 419 studies were included. Of these, 199 were primary research studies which fell under one or more of the following categories: descriptive (n = 86), qualitative (n = 75), predictors (n = 48), transition interventions (n = 21), measurement tools (n = 8), and key outcomes (n = 3). The certainty of the evidence for specific interventions and tools was generally low.RecommendationsThe panel issued strong recommendations for integrated, collaborative transition approaches involving YYAs, families, and providers, and for the use of the Transition Readiness Assessment Questionnaire (TRAQ) to support transition planning. Additional recommendations are included, with an emphasis on future research focused on long-term outcomes such as care continuity and treatment retention.ConclusionThis research addressed the absence of a cohesive approach to transitions for YYAs experiencing EDs and/or mental health conditions, highlighting evidence variability and the need for a unified approach. These guidelines propose actionable steps for improving care transitions for YYAs with EDs and/or mental health conditions by promoting collaborative care models, prioritizing outcome-focused research, and using measurement tools.