Aim: Non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly preferred over vitamin K antagonists (VKAs) in atrial fibrillation (AF) management. However, differences in oral anticoagulant (OAC) prescribing according to patient's age, sex and physician's specialty may be present. Therefore, incident and prevalent use of OACs, NOACs and VKAs, stratified by age, sex and prescriber, and factors associated with the choice of OAC were investigated. Methods: Using two Belgian nationwide healthcare databases, AF patients ≥45 years old with ≥1 OAC prescription claim between 2013 and 2019 were identified. OAC use was investigated per half-year. Factors influencing NOAC vs. VKA initiation were identified by multivariable logistic regression. Results: Among 448 661 included OAC-treated AF patients, 297 818 were newly treated. Incident OAC use ranged from 45–49 to 42–44 users/10 000 persons between 2013 and 2019, whereas prevalent OAC use increased from 337 to 435 users/10 000 persons. Incident and prevalent NOAC use exceeded VKA use since 2013 and 2015, respectively, and NOACs represented 92% of incident and 81% of prevalent OAC users in 2019. Apixaban was the most frequently used NOAC since 2016. NOACs were significantly more prescribed by cardiologists and to older patients, whereas VKAs were more initiated in patients with cardiovascular, renal and hepatic comorbidities. Prevalent OAC use increased less in women than men (25.3% vs. 33.0% between 2013 and 2019) and female subjects had 5% significantly lower odds of NOAC vs. VKA initiation than men. Conclusion: Since 2013, prevalent anticoagulant use increased almost one third in Belgium, while incident use was stable. Potential (N)OAC underuse in women requires further exploration.