Coupled-line baluns with common-mode compensation are provided herein. In certain configurations, a series resistor-inductor (RL) network is connected to ports of a coupled-line balun to null the common-mode transmission coefficient at a desired frequency. This extends performance at lower frequencies by improving the low frequency amplitude and phase balance of the device. The inductor and resistor can be connected in series between one of the differential terminals and a single-ended grounded terminal. This advantageously can null the common-mode transmission at a specific frequency near a minimum length-dominated frequency so as to enhance the common-mode rejection at lower frequencies.