Objectives: This study aimed to investigate the relationship between anger and manner of anger expression with self-care agency in individuals diagnosed as having hypertension. Methods: This descriptive and cross-sectional study was carried out in 305 patients with hypertension. Data were collected using the Self-Care Agency Scale, the Trait Anger and Anger Expression Scale and Individual Identity Form, and were evaluated by percentage, mean, standard deviation, and correlation analysis. Results: The mean trait anger score was 21.13 +/- 6.61; the mean internalized anger score was 19.44 +/- 4.94; and the mean externalized anger score was 13.10 +/- 4.49. The mean anger control score was 23.40 +/- 4.97, and the mean self-care agency score was 103.87 +/- 19.31. Conclusion: There was a negative correlation between trait anger, internalized anger, externalized anger and self-care agency scores. When trait anger, internalized anger and externalized anger scores increased, the self-care agency decreased. However, there was a positive correlation between anger control and self-care agency. When anger control score increased, the self-care agency score also increased.