Abstract: The present invention presents a stretching frame for fabric materials such as an artist's canvas which can be easily assembled and disassembled, while providing superior rigidity. Unique inner frame members interlock orthogonally along the inner length of outer frame member to prevent the tension of the canvas from deflecting the frame inwardly. Half lapped joints at the corners of the inner frame members provide additional strength for the frame and the ability to adjust the tautness of the canvas in either a single direction or two directions by the insertion of wedges or turnbuckles.