A voltage generator includes: a first pump configured to generate and output a first voltage to a first node in response to a first clock signal; a second pump configured to generate and output a second voltage to a second node in response to the first clock signal; a third pump configured to generate and output a third voltage to the first and second nodes in response to the first clock signal; a first switch configured to deliver the third voltage to the first node in response to a first control signal; and a second switch configured to deliver the third voltage to the second node in response to a second control signal, in which the first pump has a first drivability, the second pump has a second drivability, and the third pump has a third drivability greater than the first and second drivabilities.