Provided are a composite optical sheet and a liquid crystal display device including the same. The composite optical sheet includes: a first optical functional layer having a first surface and a second surface, the first surface including a reference plane and a pattern of recesses dented from the reference plane; a first support layer disposed on the first surface of the first optical functional layer; a first adhesive layer disposed between the first optical functional layer and the first support layer, wherein the first optical functional layer is coupled with the first adhesive layer by penetrating into the first adhesive layer at least partially; a second optical functional layer disposed on the first support layer and including a pattern of prisms extended in a first direction; a polarizing layer disposed on the second optical functional layer; and a second adhesive layer disposed between the second optical functional layer and the polarizing layer, wherein the second optical functional layer is coupled with the second adhesive layer by penetrating into the second adhesive layer at least partially.