Provided are a switching regulator and a power management unit including the switching regulator. A switching regulator configured to transform an input voltage and generate an output voltage includes a first regulating circuit configured to regulate the input voltage and to generate a first voltage based on a first switching signal set having a first duty ratio, and a second regulating circuit configured to regulate the first voltage and to generate the output voltage based on a second switching signal set having a second duty ratio. The switching regulator determines a voltage gain based on the first duty ratio and the second duty ratio, the voltage gain corresponding to a ratio of the output voltage to the input voltage.