Passive noise control by modification of structural geometry moves more and more into the field of vision for designers. This structural–acoustic optimization shows high potential in minimization of radiated noise especially for thin shell geometries. Since computer systems have been enhanced dramatically in recent years numerical simulation of structural vibration and acoustic field was accelerated significantly. But still the sensitivity analysis represents the bottle neck in computational efforts of gradient-based optimization. Furthermore, the coupling between FE and BE analysis in structural–acoustic simulation of large scale models will occur as an additional challenge because of non-matching meshes. In this paper, a fast method for computation of sensitivities of acoustic properties with respect to shell geometry is presented. Therefore, a concept to parameterize the structural geometry is explained. Additionally, the coupling procedure is simplified to reduce computational effort. Finally, this method is applied to an academic example. The sensitivity of the sound pressure at an internal point of an oblique box is investigated, when one side of this six-sided box is geometrically modified.