A vehicle-body structure of a vehicle, comprising: an opening-portion-forming vehicle-body frame member (10, 20, 31, 40) forming an opening portion for entrance at a vehicle side part; a side door provided so as to open and/or close the opening portion; and a vehicle-width-direction-extending vehicle-body frame member (17, 26, 36, 47) extending in a vehicle width direction from a portion, in a peripheral direction of the opening portion, of the opening-portion-forming vehicle-body frame member (10, 20, 31, 40), wherein the side door comprises a door panel portion and a reinforcement portion (71, 72, 73, 74), the door panel portion being provided to cover the opening portion and configured such that a peripheral part (63, 64, 65, 67) thereof overlaps with the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in a vehicle side view, the reinforcement portion (71, 72, 73, 74) being provided at the peripheral part (63, 65) of the door panel portion such that the reinforcement portion (71, 72, 73, 74) overlaps with the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view, thereby reinforcing the peripheral part (63, 64, 65, 67) of the door panel portion against a collision load applied to the side door from a vehicle side, and the reinforcement portion (71, 72, 73, 74) is provided at a portion of the peripheral part (63, 64, 65, 67) of the door panel portion which includes a part located at or corresponding to the vehicle-width-direction-extending vehicle-body frame member (17, 26, 36, 47), wherein the reinforcement portion is provided to overlap with an upper-side side-sill flange and a side-sill side wall portion of a side sill which particularly constitutes the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view, characterized in that the reinforcement portion is provided to overlap with a hinge-pillar side wall portion of a hinge pillar which particularly constitutes the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view, and the reinforcement portion is provided to overlap with a roof-side flange of a roof side rail which particularly constitutes the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view. an opening-portion-forming vehicle-body frame member (10, 20, 31, 40) forming an opening portion for entrance at a vehicle side part; a side door provided so as to open and/or close the opening portion; and a vehicle-width-direction-extending vehicle-body frame member (17, 26, 36, 47) extending in a vehicle width direction from a portion, in a peripheral direction of the opening portion, of the opening-portion-forming vehicle-body frame member (10, 20, 31, 40), wherein the side door comprises a door panel portion and a reinforcement portion (71, 72, 73, 74), the door panel portion being provided to cover the opening portion and configured such that a peripheral part (63, 64, 65, 67) thereof overlaps with the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in a vehicle side view, the reinforcement portion (71, 72, 73, 74) being provided at the peripheral part (63, 65) of the door panel portion such that the reinforcement portion (71, 72, 73, 74) overlaps with the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view, thereby reinforcing the peripheral part (63, 64, 65, 67) of the door panel portion against a collision load applied to the side door from a vehicle side, and the reinforcement portion (71, 72, 73, 74) is provided at a portion of the peripheral part (63, 64, 65, 67) of the door panel portion which includes a part located at or corresponding to the vehicle-width-direction-extending vehicle-body frame member (17, 26, 36, 47), wherein the reinforcement portion is provided to overlap with an upper-side side-sill flange and a side-sill side wall portion of a side sill which particularly constitutes the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view, characterized in that the reinforcement portion is provided to overlap with a hinge-pillar side wall portion of a hinge pillar which particularly constitutes the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view, and the reinforcement portion is provided to overlap with a roof-side flange of a roof side rail which particularly constitutes the opening-portion-forming vehicle-body frame member (10, 20, 31, 40) in the vehicle side view.