Background: Autobiographical memory plays a key role in self-understanding and psychological health. While deficits in autobiographical memory are well-established in autism, few studies have focused on adolescence; a critical period for the developing self and self-esteem. Method: 16 adolescents with an autism spectrum disorder (ASD) and 16 typically developing adolescent controls matched for IQ and gender, were asked to provide three self-defining and three everyday memories. Participants rated their memories for emotional intensity, visual perspective and the extent to which they were self-revealing. Memories were independently rated as self-defining or everyday experiences, and according to their valence and theme. Self-esteem and depressed mood were further assessed with self-report questionnaires. Results: There were no group differences in the ability to recognise self-defining memories as assessed by independent reports. Both groups also reported their self-defining memories to be more intense than their everyday memories. However adolescents with ASD, in contrast to non-ASD controls, reported self-defining memories to reveal less about them than everyday memories. Relative to controls, they retrieved fewer memories with an achievement theme and more memories with a recreational theme. The control group showed a bias towards retrieving positive rather than negative self-defining memories but the ASD group showed no such tendency. Self-esteem, but not mood was poorer in the ASD group and self-esteem was related to the retrieval of negative self-defining memories. Conclusions: Adolescents with ASD exhibit an instable self-representation; they recognise the types of past experiences that define them but feel weak connections with these memories. (C) 2017 Elsevier Ltd. All rights reserved.