Gender-typical play is observed throughout childhood for non-autistic children. However, there has been limited research into the gender typicality of autistic children’s play compared to that of non-autistic children. In a longitudinal population-based cohort, we compared gendered play behaviours in autistic and non-autistic children using standardised parent-report (30, 42 and 57 months) and child-report (8 years) data (N= 11,251). We observed no difference in gendered play behaviours between girls with or without autism at any time point. Autistic and non-autistic boys did not differ in the gender typicality of their play when aged 30 months, but the play of autistic boys appeared less masculine than that of non-autistic boys (β = −1.1, 95% confidence interval = −2.1 to −0.2; and β = −2.6, 95% confidence interval = −4.7 to −0.5) at 42 and 57 months. Autistic boys also self-reported less masculine play behaviours than non-autistic boys at 8 years of age (β = −3.4, 95% confidence interval = −6.6 to −0.2). We found that autistic boys’ play was less gender typical than that of non-autistic boys in middle and later childhood. Our findings highlight the importance of examining gendered play behaviours in a developmental context and have relevance for understanding the development of gender identity in autism.Lay abstractNon-autistic children tend to show gendered patterns of play behaviours – boys are more likely to play with ‘masculine’ toys, and girls are more likely to play with ‘feminine’ toys. However, little is known about whether autistic children follow these patterns as well. We looked at the masculinity and femininity of autistic and non-autistic children’s play behaviours at multiple time points. Parents reported their children’s play behaviours at ages 30, 42 and 57 months, and children reported their own play behaviours at 8 years old. We found no difference between autistic and non-autistic girls, who both showed more feminine play behaviours as they got older. Autistic boys’ play behaviours were reported as less masculine than non-autistic boys at 42 and 57 months, and at 8 years old. We also found that non-autistic boys’ play tended to become more masculine as they got older, but this was not the case for autistic boys. Our findings suggest that differences in autistic and non-autistic boys’ play behaviours may develop at around 42 months old.