BACKGROUND: Atrial fibrillation is a leading cause of emergency medical services (EMS) use, but sex differences across prehospital, hospital, and postdischarge care remain poorly characterized. METHODS: We performed a population-based linked cohort study of adults attended by EMS for atrial fibrillation in Victoria, Australia, from January 1, 2015, to June 30, 2019. EMS records were linked to emergency department, hospital admission, and death data sets. Multivariable models evaluated sex differences in care and outcomes. RESULTS: Among 16 415 atrial fibrillation EMS attendances, 9329 (56.8%) were in women, median age 76 years. Age-standardized attendance rates were higher in women (77 versus 57 per 100 000 person-years; incidence rate ratio, 1.35 [95% CI, 1.33-1.38]), especially in metropolitan areas and adults aged ≥70 years. Women had lower odds of prehospital treatment (56% versus 62%; adjusted odds ratio [aOR], 0.85 [95% CI, 0.79-0.92]) and mobile intensive care paramedic attendance (aOR, 0.85 [95% CI, 0.78-0.93]). Presentation-conditioned aspirin and appropriate analgesia did not differ by sex. Women had fewer cardioversions (aOR, 0.79 [95% CI, 0.70-0.89]) but similar ablation rates (aOR, 0.95 [95% CI, 0.83-1.10]), higher 30-day and 6-month EMS reattendance (adjusted hazard ratios [aHRs], 1.29 and 1.35), and lower 30-day and long-term mortality (aHRs, 0.83 and 0.71). CONCLUSIONS: Women attended by EMS for atrial fibrillation had lower global prehospital treatment, higher reattendance, and lower mortality than men, supporting standardized prehospital pathways and rapid-access follow-up.