An image forming system includes a plurality of image forming apparatuses and a group management server. The plurality of image forming apparatuses each include a document-box management unit. The document-box movement processing unit transmits a command to at least one of a first image forming apparatus assigned to a group before the movement and a second image forming apparatus assigned to a group after the movement, the command causing movement of a document box of the moved user from the first image forming apparatus to the second image forming apparatus. The document-box management unit in at least one of the first image forming apparatus and the second image forming apparatus accepts the command. The document-box management unit forwards the document box of the moved user from the first image forming apparatus to the second image forming apparatus.