A technique for the seismic retrofit and rehabilitation of existing welded steel plate edge connections between precast concrete shear wall panels using carbon fiber reinforced polymer (FRP) composite sheets is presented. Nine lateral load tests were performed on shear wall assemblies comprising three 4 x 12 ft x 8 in. (1.22 x 3.66 m x 203 mm) hollow-core precast concrete wall panels. Each wall assembly was loaded in the in-plane direction by quasi-static simulated seismic loads. The test variables were the covered area of FRP composite sheets, the number and orientation of FRP composite layers, and wall panel surface preparation. Concrete surface preparation using high-pressure water jet and subsequent application of a bonding agent resulted in the most effective bond between concrete and FRP composite. The tests demonstrated that FRP composite connections could transfer the applied load across the joint effectively and achieve a higher capacity compared to welded steel plate edge connectors.