In this paper, we propose a low-power piezoelectric speaker driver for acoustic communication based on on-off keying modulation. To reduce the dynamic power consumed to drive the capacitive speaker, the proposed driver is implemented using an LC oscillator. A proof-of-concept prototype is implemented using off-chip components, and experimental results show that the proposed LC oscillator based on-off keying reduces the power consumption by nearly 50 % compared to a conventional driver.