The steel slit panel–frame is a new system for seismic resistance of buildings. The steel slit panels are bolted to beams which are simply connected to the columns. The steel slit panels are steel plates with rows of vertical slits forming a series of flexural members within the plate. The steel slit panels are designed to resist the entire lateral load and provide all the stiffness and energy dissipation in the system. The steel slit panel–frame system was studied via an experimental program, divided into two series of testing. The first series studied the fundamental characteristics of the steel slit panels, while the second series studied the behavior of the steel slit panels within the frame (i.e., behavior of the steel slit panel–frames). A concise introduction to the system is presented first, followed by the findings from the experimental study.