'Theory of Mind' (ToM) is the ability to attribute mental states to others to make sense of their behaviour. ToM research has informed understanding of (a)typical social behaviour, including the symptoms of autism spectrum disorder (ASD). This began with research on ToM in autistic children and there has been a noticeable increase in the study of ToM in autistic adults. However, methodological limitations in adult ToM research may be limiting its explanatory power of ASD symptoms and their management, therefore we discuss recent advances in measuring ToM aimed at addressing these issues. We also examine previously overlooked approaches and propose several new directions that have potential to improve the sensitivity, accuracy, and clinical utility of ToM measurement in autistic adulthood.