Psychosexual functioning is an important aspect of human development and relationships. A previous study investigated psychosexual functioning of autistic adolescents using the Teen Transition Inventory (TTI), but there is a lack of comprehensive measurement of psychosexual functioning among autistic and non-autistic (NA) adults. To address this gap, the current study adapted the self-report TTI to the Psychosexual Functioning Survey (PSFS) and presented it to 131 autistic (n = 59) and NA adults (n = 72) in the U.S. Comparisons of psychometric properties between the original TTI and the PSFS are shared; the developmental relevancy among some items was changed, and the alphas indicated a difference in the content of certain scales. Differences emerged between autistic and NA adults in both the intra- and interpersonal domains of psychosexual functioning, but not in sexual and intimate behaviors. The findings suggest the persistence of differences from adolescence to adulthood between autistic and NA people and highlight the importance of understanding the unique experiences of adults in psychosexual functioning relative to diagnostic status.