Transmission-line filtering with enhanced frequency response is disclosed. In an example aspect, an apparatus includes a transmission-line filter to enhance a frequency response of a filtering operation. The transmission-line filter includes an input port, an output port, and multiple transmission-line base units. The multiple transmission-line base units are disposed between the input port and the output port and are coupled to the input port and the output port. Each of the multiple transmission-line base units includes a respective transmission line of multiple transmission lines. At least one transmission-line base unit of the multiple transmission-line base units includes a multi-resonant circuit.