<p>Cancer is a significant global health issue that requires innovative methods for diagnosis and treatment. Gold nanoparticles (AuNPs) are becoming more popular due to their unique physical and chemical properties, having ability to interact with biological systems without causing harm, and their ease of modification. This paper examines the potential of AuNPs to transform cancer theranostic via the integration of diagnostics and treatment. We explore the use of AuNPs in cancer imaging, specifically examining their ability to enhance contrast in several imaging techniques, enabling the early and accurate detection of tumors. In addition, we discuss the use of AuNP-mediated photothermal therapy (PTT), where AuNPs convert light into heat to selectively destroy cancer cells. In addition, we are exploring the capacity of AuNPs to serve as carriers for drug delivery, enabling the specific delivery of chemotherapeutic agents to tumor sites while reducing the overall negative effects on the body. One of the key advantages of AuNPs emphasized in this review is their ability to integrate therapeutic and imaging characteristics. We analyze the current challenges and propose strategies to improve the delivery and design of AuNPs for more effective cancer theranostic. AuNPs show great potential for personalized and effective cancer treatment since they may connect diagnosis and therapy.</p>