Embodiments of a multi-mode transition circuit for a DC-DC converter and a DC-DC converter are disclosed. In an embodiment, a multi-mode transition circuit for a DC-DC converter includes a transconductance amplifier operably connected to a first resistor-capacitor (RC) network and switches, a comparator operably connected to a second RC network, where the first and second RC networks are operably connected to a reference voltage, a multiplexer operably connected to the transconductance amplifier and the comparator, and an operation mode selector configured to enable or disable the transconductance amplifier and turn on or off the switches in a sequence when transitioning between a pulse-frequency modulation (PFM) mode and a pulse-width modulation (PWM) mode.