A door glass assembly is configured to reduce an impact noise generated when a door glass is moved upward/downward and may include a carrier plate coupled to a glass holder to which a door glass of a vehicle is secured. The carrier plate is installed inside a door of the vehicle so as to be movable upward/downward. A module plate, on which the carrier plate is installed so as to be movable upward/downward, is installed inside the door of the vehicle. A driving motor is provided to move the carrier plate upward/downward. The module plate and the carrier plate are provided with an impact noise preventing means for gradually decelerating and stopping the carrier plate when the door glass is being maximally moved upward or downward.