A sheet folding system includes a plurality of sheet folding apparatuses configured to receive and perform a folding process on a sheet and circuitry configured to distribute sheets to the plurality of sheet folding apparatuses. Each of the plurality of sheet folding apparatuses includes a folding device configured to fold the sheet, a first conveyance passage configured to convey the sheet downstream in a sheet conveyance direction without passing through the folding device, a second conveyance passage configured to convey the sheet to the folding device, a third conveyance passage configured to convey the sheet from the folding device downstream in the sheet conveyance direction, and a junction between the first conveyance passage and the third conveyance passage. The circuitry controls sheet conveyance to prevent an interference, at the junction, between the sheet conveyed from the first conveyance passage and the sheet conveyed from the third conveyance passage.