While cognitive flexibility challenges are frequently reported in autistic individuals, inconsistencies in the findings prompt further investigation into the factors influencing this flexibility. We suggest that unique aspects of the predictive brain in autistic individuals might contribute to these challenges, potentially varying by sex. Our study aimed to test these hypotheses by examining cognitive flexibility under different predictability conditions in a sample including a similar number of males and females. We conducted an online study with 263 adults (127 with an autism diagnosis), where participants completed a flexibility task under varying levels of predictability (unpredictable, moderately predictable, and predictable). Our results indicate that as task predictability increases, performance improves
however, the response time gap between autistic and non-autistic individuals also widens. Moreover, we observe significant differences between autistic males and females, which differ from non-autistic individuals, highlighting the need to consider sex differences in research related to the cognition of autistic individuals. Overall, our findings contribute to a better understanding of cognitive flexibility and sex differences in autism in light of predictive brain theories and suggest avenues for further research.