Research in the general population has shown that nostalgia is associated with greater wellbeing through increased authenticity. It is well documented that autistic versus non-autistic individuals experience reduced wellbeing. This is the first study to explore nostalgia in autistic people and whether nostalgia might support the wellbeing of autistic people in the same way as non-autistic. This study had two aims: (i) to explore the autistic experience of nostalgia (proneness, triggers of nostalgia, related affect) and (ii) to examine the interrelationships at trait level between nostalgia, authenticity and wellbeing in autistic and non-autistic young adults. Participants (n = 230) completed an online questionnaire and reported about their nostalgic experiences, wellbeing, authenticity and autistic traits. Participants also wrote about either a nostalgic oran ordinary memory and rated how happy they felt after reflecting on the memory. With regards to the interrelationships at trait level within the whole cohort, nostalgia was not associated with increased authenticity or wellbeing. In contrast, authenticity was associated with increased wellbeing. However, nostalgia was not associated with greater wellbeing through increased authenticity. Differences in these interrelationships between autistic and non-autistic individuals are also discussed. The autistic experience of nostalgia was similar to the non-autistic, with the exception that autistic participants were less prone to nostalgia. At state level, findings also suggested that reflecting on nostalgic memories may boost positive affect in autistic as well as non-autistic individuals. This study may have implications for boosting wellbeing in autistic people.