In this work, the structural and electronic properties of Cu, Li, and O-doped phosphorene/hexagonal boron nitride systems were studied based on density functional theory calculations. The intrinsic physical properties of the pristine phosphorene layer do not change with the addition of hexagonal boron nitride layers. While doping of phosphorene leads to strong binding energy at the interface, hence, improving the stability of the doped phosphorene/hexagonal boron nitride layers in systems. The electronic properties of the encapsulated systems change after doping. The band gap also decreases from 1.1200 eV in pristine encapsulated phosphorene to 0.3087, 0.0076, and 0.3100 eV in encapsulated phosphorene doped with Li, Cu, and O, respectively. The partial density of states and band structure diagrams show that the electronic properties of these systems shift from semiconductor to metallic behavior which can be exploited in electronic and optical applications.