Electrical conduction properties of undoped and 1 mol% Sr-doped LaP3O9 glasses and glass-ceramics were investigated over the temperature range of 673-1123 K. Both the materials showed relatively low conductivities in the glassy state. However, the conductivity of the Sr-doped LaP3O9 glass significantly increased with a heat treatment above the crystallization temperature, while the conductivity of the undoped LaP3O9 glass did not improve even after the heat treatment. It was concluded that crystallization of the Sr-doped LaP3O9 glass induced protonic conduction and thus enhanced the conductivity. Electrical conduction properties of the Sr-doped LaP3O9 glass-ceramic fundamentally resembled those of the sintered crystalline Sr-doped LaP3O9.