Transcranial magnetic stimulation (TMS) is a noninvasive neurotechnology that delivers magnetic power to the cortical targets for modulating the neural activities and achieving therapeutic goals. Currently, modalities of TMS have attracted considerable attention as a safe and effective intervention for treating different types of age-related brain disorders, including depression, Alzheimer’s disease (AD), and Parkinson’s disorder (PD). Besides of treatment effects, unrevealing the heterogeneity in treatment responses and neuroplastic effects of TMS at different biological scales, and how the effects interact with each other at individual level allow the neuroscientists understand the biological effects of TMS, provide brain-based evidence for dose estimation in aging populations, and develop personalized TMS therapeutic plans for neurocognitive disorders (NCD). In this chapter, we describe the clinical applications of TMS in NCD and the evidence for TMS-induced treatment effects and neuroplasticity. We also describe the predictive capacities of imaging biomarkers, with a focus on magnetic resonance imaging (MRI) and discuss the potential ways to enhance future research opportunities in treating NCD with TMS.