A voltage generator for a semiconductor memory device that improves the drivability of an output driver by controlling a gate of the output driver to vary between an internal power supply voltage and a ground voltage, is disclosed. The voltage generator includes an output voltage controller to generate a pull-up signal for controlling a pull-up operation and a pull-down signal for controlling a pull-down operation, the pull-up signal having a level substantially equivalent to an internal power supply voltage if a cell plate voltage is higher than a cell plate reference voltage, and having a level below the cell plate voltage if the cell plate voltage is lower than the cell plate reference voltage. The voltage generator further includes an output driver to generate a stable cell plate voltage in response to the pull-up signal and the pull-down signal.