BACKGROUND: Research indicates dissociative experiences (DE) are prevalent in adolescents. However, the exact phenomenology and underlying mechanisms of dissociation in adolescence have yet to be clarified. The current study explores the presentation of, and possible psychological factors maintaining, dissociation in this population. METHODS: Two online self-report surveys captured data from 3076 adolescents aged 13-18 years. Participants completed the Černis Felt Sense of Anomaly (ČEFSA) scale of felt sense of anomaly-type dissociation, alongside measures of mechanisms chosen to test the relevance of a cognitive-behavioural model of dissociation in adults (cognitive appraisals, alexithymia, healthy affect regulation, and affect intolerance in the form of expressive suppression (ES)). N = 409 completed the ČEFSA scale at a second timepoint, one month later, enabling exploration of proposed maintenance factors. RESULTS: Most (91.87%) adolescents endorsed at least one ČEFSA item. The mean number of endorsed items was 13.00 (SD = 9.67). The most endorsed factors of the ČEFSA were Altered Sense of Agency (82.96%), Anomalous Experience of the Self (76.76%), and Altered Sense of Connection (73.76%). Mediation analysis indicated that affect intolerance (ES) mediated the relationship between Time One and Time Two dissociation scores: greater suppression was associated with greater dissociation 1 month later. No other tested variables showed statistically significant mediation. CONCLUSION: Adolescents are likely to experience dissociation as detachment and disconnection, particularly relating to their selfhood and external world (i.e., depersonalisation and derealisation). This study suggests that the key element of a recent cognitive-behavioural model of DE in adults-that affect intolerance perpetuates dissociation-may also be applicable in adolescence.