Gold nanoparticles (GNPs) are emerging as promising agents for cancer therapy, with applications in drug delivery, photothermal therapy, contrast imaging, and radiosensitization. This review highlights recent advancements in GNP research, focusing on their potential as sensitisers with ionizing radiation. GNPs exhibit unique physicochemical properties, such as surface plasmon resonance and the ability to bind amine and thiol groups, which enhance their biomedical applications. In drug delivery, GNPs can be functionalized to target specific receptors, improving drug efficacy and reducing side effects. Photothermal therapy using GNPs involves converting absorbed energy into heat, which can selectively damage cancer cells. GNPs also provide enhanced contrast in imaging modalities like CT and MRI, aiding in tumor detection and treatment planning. Radiosensitization, where GNPs enhance the effectiveness of radiation therapy, has been observed at both kilovoltage and megavoltage energies. However, the exact mechanisms of radiosensitization remain unclear. In vivo studies have shown promising results, with GNPs improving tumor growth delay and survival rates. Despite these advancements, further research is needed to address issues such as biodistribution, toxicity, and long-term effects. The Nanotechnology Characterization Laboratory (NCL) is working to standardize pre-clinical characterization of nanomaterials, facilitating their translation into clinical trials. The potential of GNPs in cancer therapy is significant, but rigorous testing and optimization are essential before routine clinical use.Gold nanoparticles (GNPs) are emerging as promising agents for cancer therapy, with applications in drug delivery, photothermal therapy, contrast imaging, and radiosensitization. This review highlights recent advancements in GNP research, focusing on their potential as sensitisers with ionizing radiation. GNPs exhibit unique physicochemical properties, such as surface plasmon resonance and the ability to bind amine and thiol groups, which enhance their biomedical applications. In drug delivery, GNPs can be functionalized to target specific receptors, improving drug efficacy and reducing side effects. Photothermal therapy using GNPs involves converting absorbed energy into heat, which can selectively damage cancer cells. GNPs also provide enhanced contrast in imaging modalities like CT and MRI, aiding in tumor detection and treatment planning. Radiosensitization, where GNPs enhance the effectiveness of radiation therapy, has been observed at both kilovoltage and megavoltage energies. However, the exact mechanisms of radiosensitization remain unclear. In vivo studies have shown promising results, with GNPs improving tumor growth delay and survival rates. Despite these advancements, further research is needed to address issues such as biodistribution, toxicity, and long-term effects. The Nanotechnology Characterization Laboratory (NCL) is working to standardize pre-clinical characterization of nanomaterials, facilitating their translation into clinical trials. The potential of GNPs in cancer therapy is significant, but rigorous testing and optimization are essential before routine clinical use.