A rear portion structure for a motorcycle, having a tail lamp (46) disposed at a rear portion of a rear cover (42), a rear fender (44) to which a license plate (47) is attached, which is provided continuously to the rear cover (42), and a license plate lamp (48) disposed at an upper portion of the rear fender (44) so as to illuminate the license plate (47) from above wherein a rear projection (85) is formed integrally at an upper portion of the rear fender (44) such that it projects rearwardly along an upper face of the license plate lamp (48).