This chapter discusses imaging studies in insomnia and in association with insomnia complaints in people not diagnosed with insomnia. This review includes studies applying structural and functional MRI, magnetic resonance spectroscopy (MRS), high-density electroencephalography, and transcranial magnetic stimulation (TMS). The studies reviewed have reported almost exclusively on regions of the temporal lobe, frontal lobe, and parietal lobe. These cortical regions are of interest because of their key involvement in the cognitive domains that are most affected in insomnia and after sleep deprivation. For each lobe, the chapter systematically addresses differences between insomniacs and controls and correlations of insomnia symptom severity with brain changes in both insomniacs and people not diagnosed with insomnia. Subsequently, the findings are summarized and interpreted with respect to functional relevance, pitfalls, and conclusions on cause, risk factor, or consequence. Neuroimaging has a high promise to reveal insights into the causes and consequences of insomnia.