The invention relates to a mounting frame for a switchgear cabinet or a rack, comprising mounting pieces which are arranged, as corner pieces, in the four corner sections of a rectangle or square that extends in an x-y plane, said mounting pieces being produced in a respective shaping process and having outer first and second mounting faces which extend in the x direction and in the y direction at a right angle thereto and which extend in a space direction z at a right angle to the x-y plane, and are provided with hollow spaces which are at least partially surrounded by wall parts and/or bores that are oriented in the z direction. The mounting frame further comprises intermediate elements which extend between the mounting pieces in the x direction and in the y direction and the end sections of which are fastened to the mounting pieces. The mounting pieces have wall sections which extend in parallel to the x-y plane, thus making assembly easier.