A battery module includes a module housing with a simplified assembling process and an improved energy density. The battery module includes a battery assembly configured to include a plurality of secondary batteries and has front, rear, upper, lower, left and right sides; and a module housing including a first frame located at the left side of the battery assembly and having a plate shape with opposing ends bent rightward so that bent portions thereof are respectively located at the upper side and the lower side of the battery assembly, and a second frame located at the right side of the battery assembly and having a plate shape with opposing ends bent leftward so that bent portions thereof are respectively located at the upper side and the lower side of the battery assembly and are coupled with the bent portions of the first frame, respectively.