A liquid crystal display device includes a liquid crystal panel including a first substrate having a thin film transistor and forming a transmissive region and a reflective region thereon, a second substrate facing the first substrate and a liquid crystal layer interposed between the first and second substrates and being in an electrically controlled birefringence (ECB) mode, a first optical unit attached to an external surface of the first substrate and having a first polarizing layer, and a second optical unit attached to an external surface of the second substrate and having a second polarizing layer and a compensation film interposed between the second substrate and the second polarizing layer, the compensation film having a single λ/2 film.