Background: Gastric cancer remains a major global health problem and is considered a leading cause of cancer-related mortality. Although the incidence of gastric cancer has decreased in some regions, the burden of disease remains significant, particularly in areas with a high prevalence of gastric cancer. Objective: This narrative review consolidates evidence on the influence of diet, lifestyle factors, educational level, family history of cancer, Helicobacter pylori infection, body mass index, and chronic digestive diseases on the risk of developing gastric cancer. The aim of the review is to provide recommendations based on evidence for public health strategies and identify avenues for future research. Methods: This narrative review was conducted by synthesizing results from observational studies, clinical trials, and meta-analyses. Data were extracted from PubMed, Scopus and Google Scholar and focused on studies published between 2000 and 2024. Results: High consumption of salted meat and smoking significantly increase the risk of stomach cancer, while a diet rich in fruits and vegetables and adherence to the Mediterranean diet provide protective benefits. H. pylori infection and an increased body mass index further worsen the risk, especially in combination with unhealthy eating habits. Quitting smoking and reducing alcohol consumption have been shown to reduce the risk of stomach cancer. Conclusion: Modifiable factors such as dietary habits and lifestyle are critical to prevent stomach cancer.