A sheet transport apparatus includes a transport guide that is included in a first transport path along which a sheet is to be transported and a flapper that selectively guides the sheet, which is transported by passing through the first transport path, to a second transport path and a third transport path. The transport guide has an air-blowing hole that is positioned further upstream than the flapper in a transport direction of the sheet. The sheet transport apparatus further includes an air-blowing fan that blows air to the flapper from outside the first transport path via the air-blowing hole.