The present meta-analysis was conducted to explore the relationship between autism spectrum disorders (ASD) and borderline personality disorder (BPD) and to understand how gender moderates that relationship. Although ASD and BPD have different underlying causes, they have overlapping symptomology. With increased research interest in ASD without intellectual disability or language impairment and the female autism phenotype, we determined an updated systematic literature review and meta-analysis may allow for a better understanding of the prevalence of cooccurrence of ASD and BPD. The random-effects model was used to determine the prevalence of BPD diagnosis in adults meeting criteria for ASD (BPD in ASD). Across eight studies, the pooled prevalence for BPD in ASD was 3.9%, 95% CI [1.5%, 6.3%], p = .001. The fixed-effects model was used to determine the prevalence of ASD diagnosis or traits in individuals meeting criteria for BPD (ASD in BPD). Across four studies, the pooled prevalence for ASD in BPD was 3.6%, 95% CI [0.7%, 6.6%], p = .016. No significant moderators emerged. The implications for future research and clinical applications are discussed.