A semiconductor device may include a first internal command generation circuit, a first DLL circuit, a second internal command generation circuit, and a second DLL circuit. The first internal command generation circuit may generate a first delay command in response to a first external command, a first latency, a first clock, a first delay control signal, and a second clock. The first DLL circuit may generate the first delay control signal and the first second clock in response to the first clock. The second internal command to generation circuit may generate a second delay command in response to a second external command, a second latency, the first clock, a second delay control signal, and a third clock. The second DLL circuit may generate the second delay control signal and the third clock in response to the first clock.