Adverse childhood experiences (ACEs) are thought to have negative effects on mental health and well-being in adolescence. The definition of ACEs varies between studies, and their measurement is mainly based on questionnaires designed for adults to recall their childhood. This scoping review aimed to explore the research methods and findings from studies that quantitatively analysed the association between ACEs and mental health, behaviour, and educational performance in adolescence (ages 12–17). We sought to map and hypothesise the links or mechanisms between ACEs and these psychosocial outcomes by narrative synthesis of the methodologies and findings of the included studies, appraised with the Cambridge Quality Checklist. We searched MEDLINE, EMBASE, and PsychINFO from 1998 to July 2023 for relevant studies. We identified twenty studies that measured twenty-seven “ACEs” during childhood (ages 0–17), including abuse, neglect, household dysfunction, bullying, and other adversities. The definition of and measurement tools for ACEs and the analysis techniques were heterogeneous. ACEs were commonly analysed as the exposure of interest with factors around the child and family as confounders. Statistical techniques included regression modelling, mediation analysis, structural equation modelling, and decision tree classification. Eighteen studies estimated the cumulative effects of ACEs, either as ACEs count/score or latent classes; and four studies estimated individual ACE effects. Cumulative ACEs and most individual ACEs were positively associated with increased probabilities of negative adolescent psychosocial outcomes. Measuring ACEs during childhood and the associated impacts on adolescents appeared feasible in longitudinal studies and surveys. Heterogeneous ACE classification, psychometric properties of measurement tools, and the ACE score analysis approach limit the comparability and interpretation of findings. Future studies into the prevention or effects of ACEs on adolescent well-being and development should address factors leading to ACEs or mitigating their impacts on adolescent psychosocial development, and use triangulation in the research of ACEs.