AbstractWhispering gallery modes (WGM) offer strong confinement of electromagnetic radiation to specific resonances supported by the geometry of the resonator. In fact, highest ever quality factors are reported in optical and near‐infrared WGMs along with their applications. Terahertz (THz) radiation offers a unique spectroscopic window to probe materials and has applications in security, sensing, and telecommunication. WGMs at THz have untapped potential for light–matter interaction studies and wide‐ranging applications. In this review, an educational overview of WGMs is given, followed by a review of the THz WGMs and their applications.