A two-stage low voltage self-starting circuit was designed for thermoelectric energy collection systems under low input voltages. A novel stacked inverter was introduced in the first stage to form a ring oscillator that could be used to generate large oscillation amplitudes at low supply voltages. The second stage consisted of a high-amplitude clock generation circuit and a multiplexing-inductor boost circuit, further enhancing the output voltage. The control circuit, which was constituted by voltage detection circuits and auxiliary circuits, realized the transition from the first stage to the second and from the second stage to the main boost. The circuit was design in a 0.18 μm CMOS process. As shown by the results of the post-layout simulation, at a TEG input voltage of 190 mV and a load current of 11.8 μA, the circuit could generate an output voltage of 825 mV with a conversion efficiency of 56.5%. Self-starting was realized in the energy collection system, guaranteeing the normal operations of the post-stage main boost circuits.