Disclosed is a level shifter. The level shifter includes a level shifting circuit, a first adjusting circuit, and a second adjusting circuit. The level shifting circuit determines whether to output a first current from a supply voltage line to an output node based on a voltage level of a first node and determines whether to output a second current from the supply voltage line to a third node based on a voltage level of a second node. The first adjusting circuit blocks an output of a third current from the third node to the first node when a clock signal having a first voltage level is received. The second adjusting circuit outputs a fourth current from the first node to a ground voltage line when the clock signal having the first voltage level is received.