A backlight assembly capable of preventing light leakage and a liquid crystal display (LCD) device including the same are provided. The backlight assembly includes a light source unit, a light guide plate, a light conversion sheet, and a reflective tape. The light source unit including one or more light emitting diodes (LEDs) mounted on a flexible printed circuit board (FPCB). The light guide plate is disposed to be adjacent to the light source unit. The light conversion sheet is disposed on the light guide plate and spaced apart from the FPCB, and configured to convert a wavelength band of light provided through the light guide plate from the light source unit, the light conversion sheet configured to emit white light. The reflective tape is attached to extend from a portion of an upper surface of the FPCB to a portion of an upper surface of the light conversion sheet.