--- - |2+ Several theories have attempted to characterise autism spectrum disorders (ASDs) at the cognitive level, most notably: theory of mind (ToM), executive function (EF), and a local processing bias (LB). The aim of this study was to investigate how these cognitive functions develop over time The three cognitive domains (ToM, EF, and LB) were examined in a group of high‐functioning children (age: 8–12, mean 10.85; IQ: 78–139, mean 105.48) with ASD and a matched group of children with neurotypical development (NTD) (IQ: 75–145, mean: 109.47), and several tasks were used within each domain to ensure the validity of the cognitive measures. Approximately 3 years later (mean age: 14.34), all children and their families were invited to participate in the follow‐up (ASD, N = 21; NTD, N = 30). While the understanding of other's minds does improve from childhood to adolescence, ToM impairment persists in adolescents with ASD relative to their peers. Likewise, a development in EF was observed in the ASD group, while no significant improvement was seen in the NTD group, leading the ASD group to catch up in this domain. We did not detect any group differences at any time point regarding local bias processing (LB). Individual patterns of development were seen, but remarkably, ToM deficits were present in every child with ASD in whom we could detect any cognitive impairment at baseline, and a similar pattern was found at follow‐up. These findings indicate that ToM is a persistent cognitive deficit in ASD. Lay Summary This was the first study to investigate the development of three well‐known cognitive functions into adolescence: While the understanding of other's minds improves from childhood to adolescence, adolescents with ASD are still impaired relative to their peers. The EFs, however, seem to improve to a neurotypical level in ASD as children enter adolescence, while local processing bias seems to differentiate the groups only in early childhood. - Autism Research, EarlyView.