Provided is a wiring substrate, a semiconductor device package including the wiring substrate, and methods of fabricating the same. The semiconductor device package may include a wiring substrate which may include a base film. The base film may include a mounting region and a non-mounting region. The wiring substrate may further include first wiring patterns on the non-mounting region and extending into the mounting region, second wiring patterns on the first wiring patterns of the non-mounting region, and an insulating layer on the non-mounting region, and a semiconductor device which may include bonding pads. At least one of side surfaces of the second wiring patterns adjacent to the mounting region may be electrically connected to at least one of the bonding pads of the semiconductor device.