BACKGROUND: Little is known about the friendships and relationships of autistic adults, despite decades of research evidence showing the benefits of close relationships for neurotypical adults. Even less is known about the relationships of autistic women, or how their relationships compare with those of neurotypical women. This mixed-methods study, therefore, examined differences in the social relationships of autistic women in relation to their neurotypical counterparts. METHODS: Thirty-eight women (19 autistic women, 19 neurotypical women), aged between 20 and 40 years, completed the Unidimensional Relationship Closeness Scale, The Awareness of Social Inference Test, and a semistructured interview about their current and former friendships and romantic relationships. RESULTS: In many ways, the social relationships and experiences of autistic women were much like those of neurotypical women. Autistic women, however, had greater difficulty with social inference skills, and reported experiencing more negative social situations. This was particularly the case in terms of social and sexual vulnerability, a feature that the autistic women themselves linked to their difficulties with social inference. Despite these challenges, autistic women were happier and more self-assured in their adult relationships than they remembered being in adolescence. CONCLUSIONS: These findings highlight an urgent need for specific and tailored personal safety training and support for autistic women—and, by extension, autistic girls—to ensure that they can enjoy a safe transition to adulthood and positive adult relationships. LAY SUMMARY: WHY WAS THIS STUDY DONE? At the moment, we know lots about adult friendships and relationships among neurotypical people, but we know very little about friendships and relationships for autistic adults. This is especially the case for autistic women, who are an understudied group and who are not often studied in their own right. WHAT WAS THE PURPOSE OF THIS STUDY? We wanted to find out whether autistic women have similar friendship and romantic relationship experiences to neurotypical women. We also wanted to know more about the ways these relationships had changed since adolescence—whether any changes over time were similar or different to those of neurotypical women. WHAT DID THE RESEARCHERS DO? We included 38 women in the study. Half of them were autistic and half were neurotypical. They were aged between 20 and 40 years old. They completed a questionnaire measuring the closeness of their relationships, and a test of how well they understood social situations. They also took part in an interview where we asked them about their current and past friendships and romantic relationships, and if/how these had changed over time. WHAT WERE THE RESULTS OF THIS STUDY? We found that autistic and neurotypical women had friendships and relationships that were very similar. Both groups had friends, and similar number of women in each group had partners and children. Autistic women, though, found it harder to interpret social situations, and generally reported having more difficult friendship/relationship experiences than neurotypical women. This was especially true in terms of social and sexual experiences, where autistic women reported that they were much more vulnerable to exploitation than neurotypical women. Autistic women themselves linked this to their difficulties interpreting social situations. Despite these difficulties though, autistic women were happier with their relationships and much more confident in their social skills in adulthood than they remembered being as teenagers. WHAT DO THESE FINDINGS ADD TO WHAT WE ALREADY KNEW? These findings give us new information about the social experiences of autistic women, giving them the opportunity to talk about things that have gone well alongside some of the difficulties they can face. The positive outcomes women talked about were different to those reported in autistic men (in previous research). This is important because it shows that gender shapes social experiences as much as being autistic itself. WHAT ARE THE POTENTIAL WEAKNESSES IN THE STUDY? We had to ask women to look back on their teenage years, so there is always a chance that people have misremembered things or are interpreting them differently in adulthood to how they felt at the time. Also, as only those comfortable being included as women were involved in this study, it was not possible to carry out direct comparisons between the friendships and relationships of women and men, or those of autistic nonbinary or trans people, who likely have unique experiences. HOW WILL THESE FINDINGS HELP AUTISTIC PEOPLE NOW OR IN THE FUTURE? We hope that the findings of this research will help families and professionals to better support autistic girls and women in their relationships, particularly in terms of romantic and sexual relationships, as well as education on personal safety. It also goes some way toward dismissing popular myths about autistic people struggling to make real friendships by showing a variety of successful relationships among autistic women.