In this paper the continuous adjoint method is developed for a vibroacoustic model that predicts the interior noise of a vehicle induced by the airflow. The model simulates the front side window vibration, excited by the acoustic and hydrodynamic pressure load, and the resulting sound wave propagation into the cabin. Targeting interior noise reduction, the continuous adjoint formulation is used to derive the adjoint to the state equations, namely the bending wave and the wave equations, whilst taking into consideration their coupling. The developed method is applied to a generic vehicle test body for the minimisation of the interior noise.