A vehicle cargo bed structure includes a tailgate and a tailgate gap cover. The tailgate gap cover has a first attachment structure fixedly attached to a bed floor of the vehicle cargo bed structure, a second attachment structure fixedly attached to the bed floor at a location spaced apart from the first attachment structure, and a biasing structure. The tailgate gap cover is pivotal between a horizontal orientation with the tailgate in an open position, and an upright orientation with the tailgate in a closed position. The tailgate gap cover covers a gap between the tailgate and the bed floor with the tailgate in the open position. The biasing structure extends from the first attachment structure to the second attachment structure and biases the tailgate gap cover into contact with the tailgate in both the horizontal orientation and the upright orientation.