The Steel Slit Panel (SSP) is studied for its viability as a lateral force resisting system (LFRS) for regions of high seismicity. Anticipated benefits for the SSP are architectural flexibility, as well as repair and retrofit possibilities. This paper is focused on the stiffness of the SSP frames, since it depends not only on the SSP but also on the beams bounding the panels, the position on the frame, the thickness of the panel, and other factors. The stiffness has been studied by means of finite element models (FEM). A methodology for the calculation of the stiffness is proposed in this paper.