The primary focus of the study reported in this paper is seismic rehabilitation of slab-column connections damaged under the application of lateral displacement excursions. Seven 2/3-scale interior slab-column connections were tested to quantify the effects of earthquake damage and the effectiveness of various rehabilitation techniques on repairing seismic-damaged slab-column connections and improving their two-way shear strength. Three alternatives for repairing seismic-damaged slab-column connections were experimentally evaluated: 1) installation of external carbon fiber-reinforced polymer (CFRP) stirrups; 2) application of well-anchored CFRP sheets on the tension side of the slab; and 3) installation of steel collars on the column under the slab. All techniques provided a means for repairing seismic-damaged connections and strengthening flat plate structures with inadequate two-way shear capacity. In addition, the installation of the steel collars prevented punching shear failure under the application of simulated seismic displacements and increased the lateral load capacity of nonductile slab-column connections.