Disclosed are a damper having an improved structure to effectively reduce the vibration and noise of a washing machine and a washing machine including the same. In the washing machine including a plurality of dampers of which one end is joined to a tub to reduce the noise of the tub and of which the other end is joined to a cabinet, the plurality of dampers comprises: a cylinder; a piston installed inside the cylinder to be moved by one end; and a friction member joined to the inner circumference of the cylinder to face the outer circumference of the piston. The piston may include a plurality of sections with different diameters to vary the contact with the friction member in accordance with the movement of the piston.
