A high-frequency module has a wiring board including a dielectric substrate, a line conductor that is formed on a first surface of the dielectric substrate, and a first grounding conductor layer that is formed on a second surface opposed to the first surface of the dielectric substrate, and that has a first opening and a second opening disposed around the first opening; and a waveguide that is connected to the second surface, has an opening opposed to the first opening, and is electromagnetically coupled to the line conductor. The wiring board has a vertical choke portion that at least partially extends from the second opening in a direction perpendicular to the second surface. Furthermore, a horizontal choke portion is formed between the wiring board and the waveguide, along the second surface between the opening of the waveguide and the second opening.