The present disclosure relates to an optical sheet having improved optical properties and minimized surface spots. According to one aspect of the present disclosure, provided is an optical sheet comprising: a first prism sheet which has a plurality of prisms parallel in a first direction formed on one surface thereof; and a diffusion sheet which is positioned at the surface side into which light of the first prism sheet is incident and has a plurality of protrusions formed on the surface facing the first prism sheet.