A bulk acoustic wave resonator includes a substrate including a first via and a second via, a lower electrode connection member, a lower electrode, a piezoelectric layer, an upper electrode, and an upper electrode connection member spaced apart from the lower electrode connection member. The lower electrode, the piezoelectric layer, and the upper electrode constitute a resonant portion. The lower electrode connection member electrically connects the lower electrode to the first via and supports a first edge portion of the resonant portion. The upper electrode connection member electrically connects the upper electrode to the second via and supports a second edge portion of the resonant portion. Either one or both of the upper electrode connection member and the lower electrode connection member includes a respective extension portion connected to a respective one of the first via and the second via that is disposed below the resonant portion.

An acoustic wave device and an electronic component are disclosed. The acoustic wave device includes a substrate, excitation electrodes on the substrate and a cover. The cover comprises a frame member on the substrate, and a lid member. The frame member surrounds the excitation electrodes and includes an inner wall, top surface and an outer wall. The lid member is disposed on the top surface, and includes first and second surfaces opposite to each other, and a descending part on the second surface. The second surface faces the substrate. The descending part extends downward from the second surface, and covers at least a part of the inner wall or at least a part of the outer wall. The electronic component includes the acoustic wave device on a mounting substrate via an electrically conductive bonding member, and molding resin covering the device.