A tonneau cover can include a frame, a bed cover portion located within the frame, and a gasket to form a watertight seal between the frame and a vehicle. In some embodiments, the gasket includes an attachment portion configured to connect with the frame and a compression portion attached to the attachment portion and configured to deform between the tonneau cover and the vehicle to resist water entry between the gasket and the vehicle. In some embodiments, the attachment portion is less compressible than the compression portion. In some embodiments, the attachment portion comprises a pair of arms extending outward from a stop component and the compression portion comprises a pair of bulb seals, each of the bulb seals being located below each of the arms.