The unique optical properties of lanthanide-doped nanomaterials have made them broadly attractive to a wide range of applications in chemical, physical, and biomedical fields. As an external and real-time reg-ulation tool, the magnetic field is highly useful for modulating the luminescence of lanthanide ions by spectral splitting, wavelength shifting, and intensity variation. The dynamic regulation of the lumines-cence further endows the nanosystems with many valuable optical features, extending their versatility. Here, we analyze the magnetic regulation mechanisms of luminescence, survey the structure design of magnetooptic nanosystems, highlight their advances in imaging agents, responsive probes, nanomagnets and nanogenerators, microrobots, and miniature reactors; we also identify the challenges and future opportunities for hybrid magnetooptic nanosystems.(c) 2022 Elsevier B.V. All rights reserved.