Intranasal oxytocin (INOT) has received attention as a treatment for substance use disorders including tobacco dependence. However, it is unclear whether INOT-related effects differ by sex and social functioning traits. This study examined the influence of sex and two trait social functioning measures (hostility and rejection sensitivity) on INOT effects on abstinence-related subjective measures and smoking lapse. Adults who smoked cigarettes daily (N = 64; 21-40 years; 39% female) completed trait hostility and rejection sensitivity surveys at baseline followed by three experimental sessions following 12-hr smoking abstinence. Each session, participants received a single INOT dose (placebo, 20, 40 international units [IU]) in counterbalanced order, completed withdrawal, smoking urges and affect questionnaires, and a smoking lapse analog task. Interactive effects between INOT and sex, hostility, or rejection sensitivity on all outcomes were analyzed. INOT produced differential effects as a function of sex, trait hostility, and rejection sensitivity. The 20 IU dose worsened abstinence-related subjective effects for individuals with high trait hostility. Both INOT doses decreased smoking urges for high rejection sensitivity, and the 20 IU dose increased smoking urges for low rejection sensitivity. INOT increased withdrawal symptoms, smoking urges, and feelings of anger in females but not males. INOT did not improve withdrawal symptoms during