Multilayer deposition of Ba 0 . 5 Sr 0 . 5 TiO 3 (BST50) and MgO thin films is demonstrated to be a novel approach to synthesize BST50/MgO composite thin films. In this work, we report the effect of MgO insertion layer on the structural, physical, and dielectric properties of the BST film. Various observations suggest that the multilayer film sample resulted in a composite with 3-0 connectivity having micro-MgO single crystals dispersed in a three-dimensionally connected BST matrix. For the BST50/MgO composite film, considerable reduction in the dielectric loss values was observed, which renders them very attractive for the tunable microwave device applications.