"Sex Differences in the Relationship between PTSD Spectrum Symptoms and Autistic Traits in a Sample of University Students. Background:  While growing literature is stressing the link between Autistic Traits (AT) and trauma-/stress-related disorders, in both conditions significant differences have been separately reported. Objective:  This study aims to evaluate the relationship between AT and trauma-/stress-related symptoms with respect to sex. Methods:  178 university students were assessed with the Structured Clinical Interview for DSM-5, the Trauma and Loss Spectrum (TALS) and the Adult Autism Subthreshold Spectrum (AdAS). In order to evaluate sex differences in trauma-/stress-related symptoms among subjects with higher or lower AT, the sample was split in two groups with an equal number of subjects on the basis of the median score reported on AdAS Spectrum (""AdAS high scorers"" and ""AdAS low scorers""). Results:  Females reported significantly higher TALS total score, Loss events and Grief reaction domain scores than males in the whole sample, while AdAS high scorers reported significantly higher TALS total and domain scores than AdAS low scorers. A significant interaction between high/low AdAS score and sex emerged for TALS domains, with females scoring significantly higher than males only among AdAS low scorers, specifically on Loss events, Grief reaction, Re-experiencing and Personal characteristics/Risk factors domains. Finally, among AdAS high scorers a significantly higher rate of subjects fulfilled symptomatological criteria for PTSD than among AdAS low scorers, without sex differences. Conclusion:  Our results confirm a significant relationship between AT and trauma-/stress-related symptoms, which seems to prevail on sex differences among high-risk subjects."