Autism spectrum disorder is often associated with impaired Theory of Mind (ToM), which involves reasoning about others’ mental states. A proposed reason for this impairment is altered brain activity in the temporoparietal junctions (TPJ) in autistic individuals compared to typically developed individuals. This systematic review aimed to investigate ToM in autistic individuals further and its relation to emotion understanding, empathy, and relationships, which were found to possibly be related to ToM and the TPJ. Five studies relevant to the aim were included and most of the results showed associations between ToM and different aspects of emotion understanding, empathy, and relationships. Nonetheless, further research on the topic must be done before these results can be generalized.