Disclosed herein are a power module package and a method of manufacturing the same. According to a preferred embodiment of the present invention, the power module package includes: a lead frame on which a power device and a control IC electrically connected to the power device and controlling the power device are mounted; and a thermal sheet bonded to one surface of the lead frame, wherein the thermal sheet includes first and second resin layers which include a thermal conductive inorganic filler and are added with a mixture of phenyl glycidyl ether (PGE) and alkyl glycidyl ether (Alkyl (C12 to C14) glycidyl ether), and a thermal spreader of a metal material disposed at a bonded interface which is formed between the first and second resin layers. Therefore, it is possible to easily improve a thermal property of the power module package by a thermal spreading effect due to the thermal spreader.