Background: Numerous studies have established a correlation between the Mediterranean diet and a reduced risk of breast cancer, as well as its efficacy in supporting weight management. Notably, obesity is widely recognized as a significant risk factor for the development of breast cancer. The Mediterranean diet has been shown to improve health outcomes among overweight or obese breast cancer survivors. This narrative review aims to consolidate information on the existing research interventions elucidating the benefits of the Mediterranean diet for the overall health of breast cancer survivors. Methods: Using the search terms "Mediterranean diet" and "breast cancer survivor", a total of 44 articles were identified. This review focuses on the six articles meeting the inclusion criteria, examining impacts on various health outcomes such as weight loss, quality of life, and various metabolic parameters (e.g., triglycerides, BMI, fasting glucose). Results: Most of the intervention studies examined weight loss and metabolic parameters including BMI and fat mass. The research results indicate that the Mediterranean diet effectively reduces BMI, waist circumference, and fat mass. Moreover, the data suggest that this dietary approach may support attaining a healthier BMI in overweight or obese breast cancer survivors. The data from various studies show no statistically significant findings for high-density lipoprotein, low-density lipoprotein, and total cholesterol levels. The assessment of quality of life varied across the studies, leading to challenges in reaching definitive conclusions. Conclusions: This narrative review offers a comprehensive overview of the impact of the Mediterranean diet on the health outcomes of breast cancer survivors who are overweight or obese.