A memory module includes memory devices; data buffers suitable for receiving write data transferred from a memory controller and transmitting read data to the memory controller; a buffer control signal generation circuit suitable for generating buffer control signals for controlling the data buffers, by using a command transferred from the memory controller; a command delay circuit suitable for generating an effective command by delaying the command by a delay amount of the buffer control signal generation circuit in a read operation and a write operation; a data processing circuit suitable for processing write data transferred from the data buffers and transferring processed write data to the memory devices, and processing read data transferred from the memory devices and transferring processed read data to the data buffers, in response to the effective command; and a command buffer circuit suitable for transferring the effective command to the memory devices.