An analysis is presented to determine the characteristics of the radiation from planar channeled positrons. This radiation has interesting properties as a source for the keV photon energy range, and may also be used to investigate the behavior of channeled particles and to characterize the channeling crystal. Several important aspects of this problem are considered, such as line‐broadening mechanisms, dependence of the radiation on the properties of the incident particle beam, and effects of anharmonicity in the crystal field potential. The emission has a full width at half‐maximum (FWHM) ?13%, is an order of magnitude brighter than bremsstrahlung, is tunable, is linearly polarized, and is highly directional.