Purpose: Adjuvant radiotherapy (RT), while effective in reducing cancer recurrence and improving survival rates, often comes with radiation toxicity that can adversely affect the patient’s quality of life (QoL). Evaluating toxicity after RT is crucial because it helps to identify and manage adverse effects that can significantly impact a patient’s QoL. By monitoring toxicity, we can adjust treatment plans to mitigate these effects, improve patient comfort, and ensure a better overall outcome. Therefore this study aimed to evaluate and compare QoL following 3D-conformal hypofractionated RT in breast cancer patients. Methods: We included twenty-one Malaysian women with unilateral breast cancer treated with lumpectomy (n=15) or mastectomy (n=6) followed by 3D-conformal hypofractionated RT. QoL was evaluated using the EORTC QLQ-BR45 questionnaire before, during, and after RT. Results: During RT, there was a significant increase in the mean score of the breast symptoms scale compared to baseline (p=0.002), with the most common symptoms being skin problems, followed by swelling and oversensitivity. However, these symptoms were generally mild for most patients. The other quality of life scales remained stable during RT. Post-RT, most QoL scales showed improvements compared to both baseline and during RT, with significant enhancements in the mean breast symptoms score and breast satisfaction score (all p<0.05). Conclusion: Radiotherapy negatively impacted the QoL of our breast cancer patients, specifically on the breast symptoms scale. However, these symptoms improved after 4 months, resulting in high breast satisfaction and indicating a near-excellent cosmetic outcome. Future studies with larger cohorts are essential to validate these findings, as the small sample size (n=21 at baseline; n=13 post-RT) may have limited the detection of more subtle changes