The present invention provides a wavelength conversion sheet protective film having a structure in which a first film, which includes a first substrate and a first barrier layer, and a second film, which includes a second substrate, are bonded to each other at a surface of the first barrier layer and one surface of the second substrate via an adhesive layer, wherein a thermal expansion coefficient in a TD direction in a temperature range of 30 to 90° C. is about 1.0×10−4/K or less.