One of the most widely used treatments for cancer is radiation therapy. It is crucial in managing gastrointestinal (GI) cancers and enhancing treatment outcomes when integrated with multimodal therapies. Advancements in technology like brachytherapy, external beam radiotherapy, and adaptive radiotherapy offer superior accuracy by improving tumor control and decreasing radiation exposure to neighboring healthy tissues. The emerging role of radiotherapy is discovered by recent clinical trials and evidence-based advances, aiming to overcome challenges related to radiation resistance in GI tumors to progress therapeutic conclusions by demanding innovative approaches. Overcoming resistance involves targeting tumor-specific factors such as hypoxia, DNA repair mechanisms, and the immunosuppressive tumor microenvironment. Managing side effects and toxicity is essential due to the critical location of GI tumors near radiosensitive organs such as the bowel, liver, and kidneys. Incorporating molecular biomarkers for therapeutic customization is the main focus of future developments in treating GI cancers. To overcome resistance, integrating radiotherapy with systemic therapies, such as checkpoint inhibitors and targeted drugs, shows potential outcomes. Precision and effectiveness are also being enhanced by developments in imaging and treatment planning. Research into epigenetic and genomic factors driving resistance is critical to developing novel therapeutic targets. These combined efforts aim to optimize radiotherapy for GI tumors, improving both survival rates and long-term patient outcomes.