A data processing apparatus, an image forming apparatus, an image forming method, and a printing system capable of improving processing capacity or power use efficiency are provided. At least one of a plurality of data processing apparatuses that are connected to a network stores correlation between data processing capacity and power consumption of each data processing apparatus, and selects a data processing apparatus with which power consumption required for processing a processing request produced by the at least one data processing apparatus is minimized based on the correlation between the data processing capacity and the power consumption. According to this selection, the at least one data processing apparatus transmits the processing request to the selected data processing apparatus, and receives data processed by the selected data processing apparatus.