A voltage generator includes a bias signal generator generating first to fourth bias signals using a reference voltage, the first to fourth bias signals having different voltage levels. A driving signal generator receives the first and third bias signals to generate a pull-up signal in response to a voltage level of an output terminal and receiving the second and fourth bias signals to generate a pull-down signal in response to a voltage level of the output terminal. A voltage driver pulls up and pulls down a voltage level of the output terminal in response to the respective pull-up and pull-down signals. An auxiliary driving controller disables the pull-up signal when the voltage level of the output terminal is greater than that of the reference voltage and the pull-down signal when the voltage level of the output terminal is less than that of the reference voltage.