OBJECTIVE: Motivation to change significantly impacts treatment outcomes in eating disorders (EDs). This study investigated patient-related factors associated with motivation to change in adolescents with first-onset anorexia nervosa (AN). Understanding these factors will help tailor interventions to individual needs, enhancing treatment outcomes. METHOD: Seventy-six female adolescents with first-onset AN completed the Readiness and Motivation Questionnaire (RMQ)-Dutch translation. ED symptoms, body mass index, and comorbidity (depressive, anxiety, obsessive-compulsive, autism spectrum disorder, and attention deficit and hyperactivity disorder symptoms) were analysed using linear regression analyses. As a secondary aim, the association between specific ED behaviours and motivation to change was analysed. This project was preregistered: https://osf.io/vx9ud/. RESULTS: Adolescents with more severe ED symptoms, depressive symptoms, and obsessive-compulsive symptoms, experienced lower motivation to change. The severity of ED symptoms emerged as the most important factor associated with motivation to change, specifically ED symptoms concerning weight and body shape. Additionally, laxative misuse was associated with greater motivation to change. CONCLUSIONS: The link between motivation to change and ED symptoms suggests that early treatment can improve outcomes by reducing ED symptoms and facilitating change. Furthermore, addressing depression during treatment might enhance motivation to change.