A loading dock seal for around a doorway of a building includes a vertically movable side seal and a relatively fixed head seal that are adapted to seal against the rear of a truck. As the truck is loaded or unloaded of its cargo, the resulting weight change on the truck's suspension can cause the truck to raise and lower a few inches. To minimize the truck abrading the side seal, a movable coupling allows the side seal to move with the truck's vertical movement. In some embodiments, the coupling includes antifriction elements, such as rollers and bearing pads, which smoothen the motion of the side seal. Although the head seal is relatively fixed to ensure a positive seal against the face of the building, the head seal is designed to readily deform in response to the truck's vertical movement.