Abstract: The aim of this thesis is to try to contribute to the research about adults with autism spectrum disorder (ASD) in public libraries. The two research questions this study attempts to answer are: How do the public libraries in a Swedish city work to increase accessibility for adults on the autism spectrum? And, what possibilities are there for the public libraries to help adults on the spectrum be more socially included and increase accessibility (as defined by the social model of disability) to create a more socially sustainable library? The study has two different research methods, because the lack of previous research necessitated a basic quantitative survey to start with. The survey was distributed to public libraries in a Swedish city. The results of the survey showed, with a few exceptions, that the respondents do not work for adults with ASD. In addition to the survey, a qualitative comparative analysis of international projects was made to examine different ways of working towards the group. The projects were analysed to examine ways to work towards the group, based on an understanding of barriers based on the social model of disability. The analysis showed that projects often contained an informational course on ASD and that a social network was an important component for further skills development. It is problematic, from a social sustainability perspective, when a group in society is excluded from the mind set of societal institutions. Adults with ASD are by law a prioritized group for the Swedish libraries and the work towards accessibility should reflect that.