Thermoelectric energy harvesting is the concept to convert thermal energies in an electric power. For the thermoelectric energy harvesting, a single inductor dc/dc converter using a negative Dickson multiplier is presented in this research. By merging a negative Dickson multiplier into a buck-boost converter, high voltage gain, flexible output tuning, and small power loss are attained by the proposed topology. Moreover, fewer number of switch drivers and simpler switching control are achieved than conventional hybrid boost converters, because the proposed converter with a single inductor has only one transistor switch. Through theoretical analysis, a characteristic investigation is performed regarding an example of the proposed converter with 6 diodes, 6 capacitors, a MOS-switch and an inductor, where simple formulas to clarify the converter characteristics are derived by utilizing a four-port model. Furthermore, we justify the efficacy of the proposed topology by performing the comparison among hybrid dc/dc converters with a single inductor, namely, the hybrid converter using a voltage doubler and the hybrid converter using a Cockcroft–Walton multiplier. In the comparison, computer simulations using a SPICE simulator reveal that the proposed converter achieve the best performance the compared converters. Specifically, the efficiency of the proposed converter with three multiplier stages reaches about 84% when the voltage gain is 6 and the output power is 2 W. Furthermore, some experiments verify the possibility of realization by assembling the proposed converter with three multiplier stages on a printed circuit board (PCB). In laboratory tests, maximum power efficiency of 85% and the maximum voltage gain of 6.4 are measured.