Provided is a side cover structure for a naked motorcycle that can further enhance a naked feel without involving insufficient structural strength, and can create a favorable impression of both a naked feel and a robust feel. A side cover structure for a naked motorcycle includes: a seat (1) that is retained by a hinge provided to a side of a vehicle body of the motorcycle and is openable toward a side, the seat on which a driver can sit in a closed state; an under-seat open space (S) that is provided under the seat (1) and is visible through an opening part (K) defined on a side of the vehicle body; and a side cover (a first side cover (9), a second side cover (10)) fitted to the vehicle body under the opening part (K). The side cover has a character line formed in a truss-like shape when viewed from a side.