A body structure of a vehicle includes a first panel and a second panel that form a closed cross-sectional portion, a partitioning panel that partitions the closed cross-sectional portion, and a reinforcement member disposed between the first panel and the partitioning panel, and includes a panel joining portion joined to the first panel, and a flange portion joined to the partitioning panel. A joining portion formed by the reinforcement member includes a rigid coupling portion in which the first panel and the panel joining portion are coupled to each other while being in contact with each other, and a flexible coupling portion in which the partitioning panel and the flange portion are coupled, with a damping member being provided therebetween. The partitioning panel includes an extended portion that extends from a vicinity of the flexible coupling portion toward the second panel and is joined to the second panel.