Dual-band filters simplify the system architecture considerably by replacing doubly multiplexed filters. This is especially important in base stations for wireless communications, where high-selective filtering functions are required, with very stringent requirements in size and insertion losses. For this goal, compact dual-band filters realized in air-filled metallic ridge waveguides are proposed. The dual-band approach shown in this article allows fulfilling the stringent insertion loss specifications of very selective filtering functions. The ridge waveguide resonators are placed in a canonical folded top-bottom structure layout. Coupling sections that provide cross-couplings are realized by irises opened in the intermediate wall. Given the high-order of the dual-band filter required for actual wireless applications, an efficient modeling by the mode-matching method is used. A complete challenging filter prototype with 16 poles and 10 transmission zeros with specifications of typical wireless transceivers is built and tested for verification. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:703–712, 2016.