This paper presents acoustic transducers built on edge-released MEMS structures, i.e., cantilever diaphragm and spiral-beam-supported diaphragm that are designed to release residual stress and also to avoid in-plane tension when bent. Sputter-deposited ZnO on the diaphragms is used as the piezoelectric thin film to sense and generate acoustic pressure. Typical diameter and thickness of the edge-released diaphragm are 1 mm and 1.6 µm, respectively. The maximum strain on the spiral-beam-supported diaphragm is about an order of magnitude larger than that of a cantilever diaphragm transducer for a given pressure level and diaphragm size. The spiral offers a higher sensitivity at the cost of a lower usable bandwidth and less tolerance on the fabrication process variation.