In this study, a novel high-gain quadratic boost converter with a voltage multiplier circuit is presented to give an alternative power electronic circuit for high-voltage conversion and low-to-medium power applications. The proposed converter combines the traditional quadratic boost converter and a coupled-inductor-based voltage multiplier circuit. Compared with the traditional quadratic boost converter, the proposed converter can obtain a much higher output voltage under the same duty cycle and input voltage, and can also reduce the voltage stresses in the power devices. Moreover, the serious input current ripple in the converter with coupled-inductor is reduced. Consequently, the efficiency and the reliability can be improved by using semiconductors with low-voltage level and high performance. The theoretical analysis of the proposed converter is verified by the experimental results.