Sharing resources is fundamental for human cooperation and survival. People tend to share resources more with individuals they feel close to compared to those who are more socially distant. This decline in generosity at increasing social distance is called social discounting and is influenced by both social traits and abilities, such as empathy, and non-social psychological factors, such as decision-making biases. People who receive a diagnosis of autism show differences in social interaction as well as displaying differences in non-social domains, such as more restricted and repetitive behaviours. We investigated social discounting in autism and found that autistic adults were more generous than neurotypical participants, which was driven by greater generosity to socially distant others. Crucially, we also investigated framing effects during prosocial decision-making. Autistic participants were less susceptible to whether decisions were framed as causing monetary gains, compared to preventing monetary losses, for the potential recipient. Our results support the view of ‘enhanced rationality’ in autism as participants’ prosocial decisions were less influenced by potential biasing information, such as the closeness of the recipient or how choices were framed. Therefore, the differences seen in autism, as well as posing certain challenges, can also have prosocial consequences. Lay abstract Autistic people show differences in their social behaviour. But how autism affects decisions to share resources, an important part of cooperation, was previously unclear. In our study, participants made decisions about how to share money with different people, including people they felt close to, such as a friend, and people they felt less close to, such as a stranger. We found that compared to a group of non-autistic participants, autistic adults shared more money overall and this was driven by greater generosity to strangers. The results suggest that autistic adults were more generous because they made fair decisions (an equal split of the money) more consistently regardless of how close they felt to the person they were sharing with. By showing that autistic adults display greater generosity, our results could help to change public perceptions of autism and potentially improve opportunities for autistic people.