According to the principle of neuroplasticity, early repeated and intense exposure to stimuli can lead to changes in brain structure. In line with this view, it has been argued that early interventions for autistic children could have an impact on their neural development. In the present systematic review, we synthesised the available evidence on neural outcomes after early behavioural, developmental and Naturalistic Developmental Behavioural interventions in young autistic children or children at elevated likelihood for autism. Six out of seven selected studies observed post-intervention differences in neural activity and connectivity. However, we observed significant methodological variation and limitations across studies (e.g., small sample sizes). Here we discuss the field-wide need to address these issues.