BACKGROUND: Long-term blood pressure (BP) patterns and variability may influence atrial fibrillation (AF) risk. However, whether these associations differ according to sex is unclear. METHODS: We analyzed 45,663 adults (age ≥ 40 years) from a Korean National Health Insurance cohort. Over the past decade, systolic BP (SBP) trajectories have been classified into two distinct trajectory classes: Class 1 (stable-low BP) and Class 2 (sustained-elevated BP). Visit-to-visit SBP variability, quantified as variability independent of the mean (VIM), was stratified into quartiles. The participants were followed up for incident AF between 2012 and 2019. Using sex-stratified Cox proportional hazards models, we assessed the association of SBP trajectory class and VIM with AF risk. RESULTS: Male sex (adjusted hazard ratio [HR], 1.43; P < 0.001), elevated SBP trajectory (Class 2, adjusted HR, 1.42; P = 0.015), and VIM 4Q (adjusted HR, 1.25; P = 0.007) were associated with a higher risk of AF. Additionally, older age, higher body mass index, alcohol consumption, diabetes, congestive heart failure, and myocardial infarction were independently associated with a higher risk of AF. In men, SBP trajectory Class 2 (adjusted HR, 1.47; P = 0.025) and VIM 4Q (adjusted HR, 1.25; P = 0.038) were significantly associated with an increased incidence of AF, whereas these associations were not significant in women. CONCLUSION: Long-term SBP trajectories and variability demonstrated sex-specific effects on AF risk. An elevated SBP trajectory and high variability conferred an increased risk of AF in men, but not in women. This novel finding may provide new insights into sex-specific differences in the pathogenesis of AF.