A straddled vehicle comprising: a head pipe; a down frame extending downward from the head pipe; a rear frame extending backward from the down frame, the rear frame including a front end and a rear end, the front end being connected to the down frame, the rear end being located in a higher position than the front end; a storage box supported by the rear frame; a seat disposed above the storage box; and a rear cover disposed outward of the storage box in a vehicle width direction, wherein the seat includes a seat sidewall, the seat sidewall overlapping an upper edge of the rear cover in a vehicle side view, the rear cover includes: a guide groove extending in a vehicle back-and-forth direction, the guide groove including a bottom portion, an inner wall and an outer wall, the bottom portion being located below a lower edge of the seat sidewall, the inner wall extending upward from the bottom portion, the inner wall being disposed inward of the lower edge of the seat sidewall in the vehicle width direction, the outer wall extending upward from the bottom portion, the outer wall being disposed outward of the lower edge of the seat sidewall in the vehicle width direction, and a side cover overlapping the bottom portion and the lower edge of the seat sidewall in the vehicle side view, the side cover being disposed outward of the guide groove and of the seat sidewall in the vehicle width direction, a front end of the guide groove is located in a lower position than a rear end of the guide groove so that water dropping on the guide groove is led to the front end, the rear cover further includes a first groove portion, the first groove portion extending backward and downward from a position located forward of a front end of the side cover in the vehicle side view, and the front end of the guide groove is connected to the first groove portion so that water flows backward and downward along the first groove portion, and is then discharged from the first groove portion to the rear of the vehicle. a head pipe; a down frame extending downward from the head pipe; a rear frame extending backward from the down frame, the rear frame including a front end and a rear end, the front end being connected to the down frame, the rear end being located in a higher position than the front end; a storage box supported by the rear frame; a seat disposed above the storage box; and a rear cover disposed outward of the storage box in a vehicle width direction, wherein the seat includes a seat sidewall, the seat sidewall overlapping an upper edge of the rear cover in a vehicle side view, the rear cover includes: a guide groove extending in a vehicle back-and-forth direction, the guide groove including a bottom portion, an inner wall and an outer wall, the bottom portion being located below a lower edge of the seat sidewall, the inner wall extending upward from the bottom portion, the inner wall being disposed inward of the lower edge of the seat sidewall in the vehicle width direction, the outer wall extending upward from the bottom portion, the outer wall being disposed outward of the lower edge of the seat sidewall in the vehicle width direction, and a side cover overlapping the bottom portion and the lower edge of the seat sidewall in the vehicle side view, the side cover being disposed outward of the guide groove and of the seat sidewall in the vehicle width direction, a guide groove extending in a vehicle back-and-forth direction, the guide groove including a bottom portion, an inner wall and an outer wall, the bottom portion being located below a lower edge of the seat sidewall, the inner wall extending upward from the bottom portion, the inner wall being disposed inward of the lower edge of the seat sidewall in the vehicle width direction, the outer wall extending upward from the bottom portion, the outer wall being disposed outward of the lower edge of the seat sidewall in the vehicle width direction, and a side cover overlapping the bottom portion and the lower edge of the seat sidewall in the vehicle side view, the side cover being disposed outward of the guide groove and of the seat sidewall in the vehicle width direction, a front end of the guide groove is located in a lower position than a rear end of the guide groove so that water dropping on the guide groove is led to the front end, the rear cover further includes a first groove portion, the first groove portion extending backward and downward from a position located forward of a front end of the side cover in the vehicle side view, and the front end of the guide groove is connected to the first groove portion so that water flows backward and downward along the first groove portion, and is then discharged from the first groove portion to the rear of the vehicle.