Bell pepper (Capsicum annuum L.) is a widely cultivated crop in tropical and subtropical regions, valued for its nutrient-rich fruits. Ensuring proper plant nutrition is essential for enhancing the yield and quality of bell peppers. However, to mitigate the adverse effects of chemical fertilizers on both the environment and human health, it is imperative to explore alternative enhancement methods. One promising approach is the application of methionine, which has been shown to significantly improve the yield and quality of various crops. This study aimed to assess the impact of different concentrations of methionine (0, 50, 100, and 150 mg L-1) on the vegetative growth and fruit yield and quality of bell pepper. A comprehensive evaluation of agronomic, physiological, and biochemical parameters was conducted. The findings indicated that foliar application of methionine significantly improved agronomic indices, enhanced photosynthesis rate, and notably increased fruit yield. Specifically, the application of 100 mg L-1 of methionine resulted in a 75% increase in yield and a 20% enhancement in vitamin C content compared to the untreated control.