Transferring from paediatric to adult care can be challenging. Adolescents and young adults (AYAs) with chronic health conditions need to develop a specific set of skills to ensure lifelong medical follow-up due to the chronicity of their condition. The Transition Readiness Assessment Questionnaire-French version (TRAQ-FR) is a 19-item questionnaire measuring such skills. The aims of the study were to (1) describe participant characteristics and (2) identify constructs related to, and predictors of, having learned domain-specific transition readiness skills. Participants included 216 AYAs aged 14-20 years (M = 15.93; SD = 1.35; 54.1% male) recruited from five outpatient clinics in a Canadian tertiary hospital. AYAs completed the TRAQ-FR, the Pediatric Quality of Life Inventory 4.0 (PedsQL) and a sociodemographic questionnaire. Descriptive, bivariate and binary logistic regression analyses were conducted. Overall, participants reported significantly higher scores on the Talking with Providers, Managing Daily Activities and Managing Medications subscales than on the Appointment Keeping and Tracking Health Issues subscales (F[41075] = 168.970, p < .001). At the item level, median scores (on a 5-point Likert scale) suggest that AYAs had begun practising five of the 19 skills (median scores ≥4; 'Yes, I have started doing this'), while a median score of 1 ('No, I don't know how') was found for one item ('Do you get financial help with school or work?'). At the subscale level, TRAQ-FR skills and skill gaps were related to AYAs' age, sex and PedsQL scores (ps < .05). Older and female AYAs were more likely to have begun practising specific TRAQ-FR subscale skills. Better psychosocial functioning was also related to having learned specific transition readiness skills. AYAs show several gaps in transition readiness. Targeted intervention in transition readiness skill development could take into account AYAs' age, sex and psychosocial functioning for a successful transfer to adult care.