A variable valve for a muffler may include an actuator; a valve tube having an inlet into which exhaust gas is flowed, and a first outlet and a second outlet into which the exhaust gas is discharged, and installed in a middle of a tail pipe into which the exhaust gas is discharged from a muffler; and a valve body in a ball shape rotatably installed in the valve tube, and rotatable by a rotational force delivered from the actuator to block the inlet, or to communicate the inlet with a selected one of the first outlet and the second outlet according to a rotated state of the valve body.