This thesis focuses on the design and implementation of a three-level Class D audio amplifier by applying recently developed sliding-mode quantized control. The designed controller, which consists of the analog filters and logic circuit, switches an H-bridge Class-D amplifier with a lowpass LC filter and operates it in the sliding mode, in order to achieve desired stability and high fidelity in the audio band. The experimental result shows that the lowest THD+N (total harmonic distortion plus noise) can be as low as 0.02% at 1 kHz. The performance is better than most of the available commercial products.