A encoder spacer for a spindle motor and an encoder assembly including the same are disclosed wherein the encoder spacer comprises: a body in monolithic structure made of insulation material; a first terminal electrically connected to a main PCB (Printed Circuit Board) of the spindle motor and protruded from a lateral surface of the body; a second terminal electrically connected to the first terminal via a conduction path through the body, electrically connected to an auxiliary PCB and protruded from an upper surface of the body; a substrate groove including an accommodation space for accommodating the encoder formed at an upper center of the body, wherein the auxiliary PCB slides in the accommodation space by being inserted into a both sides of the accommodation space; and a third terminal exposed at the substrate groove for electrically connecting the auxiliary PCB with the first terminal.