<p>Locally resonant metamaterial plate exhibiting mechanically sub-wavelength tunable bandgaps is utilized to simultaneously mitigate the structural vibration as well as attenuate the noise radiation inside an acoustic cavity in a coupled fluid–structure system. A typical configuration of a three-dimensional metamaterial plate consisting of a flexible plate with an array of local mass–spring–damper resonators is coupled with an acoustic cubical cavity. For the sake of comparison, the vibration responses of the structural plate in the presence and absence of the resonators are considered to investigate the vibroacoustic characteristics of the coupled fluid–structure system. The differences between the vibroacoustic responses of the acoustic cavity coupled with the conventional plain plate and the damped metamaterial plate are also outlined. The effects of resonators’ mass and damping values and their numbers on each of the unit cells in the overall array of the metadamping plate configuration on the width of the bandgaps and vibration reductions are investigated. A conducted sensitivity analysis on the uncertainty values of the absorber resonators’ mass and spring demonstrates that a coefficient of variation of 5% could affect the tunable bandgap width and the vibration reduction. The coupled system was numerically solved using finite element method. The obtained results and the sensitivity analyses can be used as cornerstone for design guideline of metamaterial plate for achieving prescribed vibroacoustic characteristics.</p>