The reading difficulties of individuals with autism spectrum disorders have been established in the literature, with particular attention drawn toward reading comprehension difficulties. Recent papers have highlighted the heterogeneous nature of reading abilities in this population by utilizing statistical methods that allow for investigations of unique reading profiles. This article extends this literature by investigating reading profiles longitudinally, to investigate the stability of reader profiles across time. Latent profile and transition analyses were conducted to establish categorically distinct reading profiles at two time points, 30 months apart. This study also examined whether age and autism symptom severity were related to the profiles at each time point. Finally, transitions between profiles at each time point were identified. Age did not predict profile membership, but there were significant differences in symptom severity that were largely stable over time. Results indicate that heterogeneous reading profiles exist within the autism population, ranging from average reading ability to severe difficulties across different reading subskills. The data from this study demonstrate that reading profiles of children and adolescents with autism spectrum disorders shift when examined across time.