Autistic people are thought to have difficulties with identifying and understanding their own emotions. This is referred to as It is important to study emotional self-awareness as people who are more able to understand their own emotions, whether they are autistic or not, are more able to respond to them appropriately, as well as to identify them in other people. It has not yet been confirmed whether autistic people have difficulties with emotional self-awareness, or if any reported difficulties are actually due to the way in which emotional self-awareness is measured in autistic people. If these difficulties do exist, it is also not known when these difficulties emerge. In this research, we reviewed 47 existing studies that measured emotional self-awareness in autistic and non-autistic adults and children. We also compared studies that measured emotional self-awareness in different ways. We found that autistic adults did seem to have poorer emotional self-awareness compared to their neurotypical peers. However, this was not the case with autistic children of age 12 years and below. Instead, differences in emotional self-awareness only seemed to emerge during adolescence. Moreover, these difficulties seemed to increase with age. These results suggest that difficulties with emotional self-awareness may not be inherent in autism. Instead, they may emerge alongside the greater social and mental health difficulties that are experienced by many autistic people during adolescence. We therefore suggest that it is important to find out more about, and subsequently support, the emotional self-awareness difficulties that autistic adolescents may encounter.