In this article, we propose a wideband fully metallic impedance-matching horn lens antenna based on glide symmetry realized in the gap waveguide technology. A multiple iterative method is adopted, which overcomes the limitation of large phase deviations at the interface of traditional lens antennas, thus increases the directivity as a result. Moreover, the glide-symmetric configurations of inner metallic pins within the gap waveguide are employed to construct the artificial dielectric lens, with the advantage of the ultralow dispersion, which is especially helpful to broaden the working bandwidth and improve the lens performance. The antenna is fed by a stepped double-ridged gap waveguide which can easily excite the antenna working in a wideband. To reduce the undesired reflections at the antenna aperture, the antenna is ended with a tapered structure as an impedance transition. A prototype of the horn lens antenna is manufactured and measured, showing a broad operation bandwidth from 12 to 18.5 GHz with S 11 less than −10 dB. The antenna can be further extended to the millimeter band due to the low losses of the gap waveguide at high frequencies and the iterative method can also be applied to other types of lens antenna designs.