Gastrointestinal (GI) cancers are among the leading causes of cancer-related morbidity and mortality worldwide, presenting a significant public health challenge. Even with medical research advancements, their incidence remains rising due to modifiable and non-modifiable risk factors across lifestyle, environmental, genetic, and socioeconomic factors. This narrative review identifies and synthesizes key risk factors contributing to GI cancers, including unhealthy diets (high consumption of processed foods, red meat, and added sugars), physical inactivity, obesity, smoking, alcohol use, infections (e.g., Helicobacter pylori), environmental pollution, chronic stress, and socioeconomic disparities. The review emphasizes the interaction among these factors and how this interplay is responsible for the development and progression of GI cancer. It emphasizes the importance of early detection, lifestyle modifications, and public health interventions tailored to specific populations. Understanding these interconnected risk factors provides critical insights for guiding prevention strategies, policymaking, and health education. Addressing modifiable risk factors through a comprehensive, multi-sectoral approach may significantly reduce the global burden of GI cancers and improve long-term health outcomes.