Double-leaf partitions constituted by plasterboard panels installed on steel studs creating an air-cavity or filled with sound absorbing material are widely employed in building constructions. It is well known that, due to the presence of the studs, the sound insulation of these structures is significantly lower than the theoretical value computed by neglecting mechanical connections. However, the influence of studs in the case of mechanical excitation and structure-borne sound transmission has not been thoroughly investigated. This study experimentally analyses the influence of studs on sound radiation, by comparing the radiation efficiency of a single plasterboard plate and a double-leaf partition. The vibration velocity was measured on the investigated structures, excited by an electro-dynamic shaker. The results highlight the importance of the studs’ elasticity. At higher frequencies, lower vibrational levels are measured on the radiating panel of the double-leaf system. However, at the lower frequencies, the double-leaf partition exhibited a higher radiation efficiency, probably due to the modal behaviour of the system.