This thesis is comprised of three chapters which include a systematic literature review, an empirical research paper and a critical appraisal focussing on the psychological wellbeing of autistic adults. The systematic literature review is a meta-synthesis of 12 papers and considers how psychological wellbeing is experienced by autistic women. The empirical paper is a qualitative investigation exploring the helpful factors of psychological therapy experienced by autistic adults. Semi-structured interviews were conducted with 10 autistic adults and analysed using interpretative phenomenological analysis (IPA). The clinical implications and suggestions for future research are discussed in the context of enhancing therapeutic support and psychological wellbeing for autistic adults. Lastly, the critical appraisal provides a reflective account of the findings from the literature review and empirical paper. Personal reflections of the research process are also discussed.