This study provides population-based epidemiological data on myasthenia gravis (MG) in Denmark, Finland, and Sweden, revealing trends in incidence, prevalence, and mortality. The overall incidence of MG was 1.34, 1.68, and 1.62 per 100,000 in Denmark, Finland, and Sweden, respectively, with increasing rates over time. Prevalence was 18.56, 20.89, and 23.42 per 100,000 in the three countries, also showing an upward trend. The standardized mortality ratio (SMR) for MG was 1.32, 1.23, and 1.20 in Denmark, Finland, and Sweden, respectively, with higher SMR observed in women than in men. The most common causes of death among MG patients were MG itself, chronic ischaemic heart disease, and acute myocardial infarction. The study highlights the need for improved care for MG patients, particularly young women, due to higher mortality risks. The findings emphasize the importance of healthcare planning and the need for better therapeutic management to reduce morbidity and mortality. The study also underscores the value of Nordic population-based research in understanding MG epidemiology and the importance of addressing gender disparities in disease outcomes. The study's strengths include nationwide data coverage and minimal loss to follow-up, but limitations include country-specific registry differences and data capture constraints. Overall, the study shows that MG incidence and prevalence have increased over time, while mortality has remained stable. The results provide important insights for healthcare planning and management of MG.This study provides population-based epidemiological data on myasthenia gravis (MG) in Denmark, Finland, and Sweden, revealing trends in incidence, prevalence, and mortality. The overall incidence of MG was 1.34, 1.68, and 1.62 per 100,000 in Denmark, Finland, and Sweden, respectively, with increasing rates over time. Prevalence was 18.56, 20.89, and 23.42 per 100,000 in the three countries, also showing an upward trend. The standardized mortality ratio (SMR) for MG was 1.32, 1.23, and 1.20 in Denmark, Finland, and Sweden, respectively, with higher SMR observed in women than in men. The most common causes of death among MG patients were MG itself, chronic ischaemic heart disease, and acute myocardial infarction. The study highlights the need for improved care for MG patients, particularly young women, due to higher mortality risks. The findings emphasize the importance of healthcare planning and the need for better therapeutic management to reduce morbidity and mortality. The study also underscores the value of Nordic population-based research in understanding MG epidemiology and the importance of addressing gender disparities in disease outcomes. The study's strengths include nationwide data coverage and minimal loss to follow-up, but limitations include country-specific registry differences and data capture constraints. Overall, the study shows that MG incidence and prevalence have increased over time, while mortality has remained stable. The results provide important insights for healthcare planning and management of MG.