A wheel-arch protector mounted on the rear edge of a side door for covering a wheel arch for a rear wheel, the wheel-arch protector including a protector body formed from a polymer material and a seal part formed from a polymer material that elastically deforms more readily than the polymer material for forming the protector body. The body includes a mounting baseplate, a extending plate, and a distended part. The extending plate extends from an end of the mounting baseplate to outside in a widthwise direction of the vehicle. The distended part is distended to an inner angle part of a corner between the mounting baseplate and the extending plate and has a hollow part. The seal part is comprised of a basal part formed on a vehicle-interior-facing surface of the mounting baseplate and a seal-lip part formed on the basal part.