Understanding individual differences in attitudes to autism is crucial for improving attitudes and reducing stigma towards autistic people, yet there is limited and inconsistent research on this topic. This is compounded by a lack of appropriate measures and multivariate analyses. Addressing these issues, using up-to-date measures and multiple linear regression, we examined the relative contributions of participant age, sex, autism knowledge, level of contact with autistic people, and autistic traits to attitudes towards autistic people. We found that greater autism knowledge and higher levels of contact, but no other variables, were uniquely predictive of attitudes towards autistic people. We conclude that, in addition to public awareness campaigns to raise knowledge of autism, it may be important to increase contact between autistic and non-autistic people to improve public attitudes towards autistic people.