A semiconductor stack package includes a printed circuit board (PCB), a first semiconductor chip, and a second semiconductor chip. The first and second semiconductor chips are disposed side-by-side on a first surface of the PCB to be spaced apart from each other. Each of the first and second semiconductor chips includes a command/address (CA) chip pad and a data input/output (DQ) chip pad. The CA chip pad of the first semiconductor chip is electrically coupled to the CA chip pad of the second semiconductor chip through a CA bonding wire.