Disclosed herein is a semiconductor device package including: a body including a cavity; a semiconductor device disposed in the cavity; a light transmitting member disposed on the cavity; and an adhesive layer which fixes the light transmitting member to the body, wherein the cavity includes a stepped portion on which the light transmitting member is disposed, the stepped portion includes a first bottom surface and a third bottom surface spaced apart from each other in a first direction, a second bottom surface and a fourth bottom surface spaced apart from each other in a second direction perpendicular to the first direction, a first connecting portion in which the first bottom surface and the second bottom surface are connected to each other, a second connecting portion in which the second bottom surface and the third bottom surface are connected to each other, a third connecting portion in which the third bottom surface and the fourth bottom surface are connected to each other, and a fourth connecting portion in which the fourth bottom surface and the first bottom surface are connected to each other, the adhesive layer includes a first edge portion, a second edge portion, a third edge portion, and a fourth edge portion respectively—disposed on the first to fourth connecting portions and a first extending portion disposed between the first edge portion and the second edge portion, and the first extending portion has a width which is decreased in a direction toward a center between the first edge portion and the second edge portion.