This review article discusses the development and applications of magneto-optical nanosystems in multimodal imaging and image-guided tumor therapy. Magneto-optical nanosystems, which combine magnetic and optical properties, have emerged as a robust technology for enhancing diagnostic sensitivity and accuracy in cancer diagnosis and treatment. These nanosystems integrate magnetic nanoparticles (MNPs) with optical materials, such as semiconductor quantum dots (QDs), carbon-based nanomaterials, and lanthanide-doped nanoparticles, to achieve enhanced sensitivity, dispersion characteristics, and chemical stability. The article highlights the advantages of these nanosystems, including their ability to serve as multimodal probes for MRI, fluorescence imaging (FLI), and photoacoustic imaging (PAI), and their potential for targeted drug delivery and site-specific release. The review also covers the recent advancements in the synthesis and characterization of various magneto-optical nanosystems, their applications in multimodal imaging, and future research directions. Finally, the article discusses the challenges and opportunities in the development of magneto-optical nanosystems for biomedical applications, emphasizing their potential in precision medicine.This review article discusses the development and applications of magneto-optical nanosystems in multimodal imaging and image-guided tumor therapy. Magneto-optical nanosystems, which combine magnetic and optical properties, have emerged as a robust technology for enhancing diagnostic sensitivity and accuracy in cancer diagnosis and treatment. These nanosystems integrate magnetic nanoparticles (MNPs) with optical materials, such as semiconductor quantum dots (QDs), carbon-based nanomaterials, and lanthanide-doped nanoparticles, to achieve enhanced sensitivity, dispersion characteristics, and chemical stability. The article highlights the advantages of these nanosystems, including their ability to serve as multimodal probes for MRI, fluorescence imaging (FLI), and photoacoustic imaging (PAI), and their potential for targeted drug delivery and site-specific release. The review also covers the recent advancements in the synthesis and characterization of various magneto-optical nanosystems, their applications in multimodal imaging, and future research directions. Finally, the article discusses the challenges and opportunities in the development of magneto-optical nanosystems for biomedical applications, emphasizing their potential in precision medicine.