A backlight unit capable of preventing deterioration in image quality of a display image by controlling driving timing of a backlight in consideration of an operation speed of liquid crystal, a liquid crystal display device using the same, and a method for driving the backlight unit are disclosed. The backlight unit includes a backlight including a plurality of light sources to generate light, and a backlight control unit configured to control an on/off time of the backlight in units of at least one frame using an off time setting value set by a user and an external dimming control signal and to control the amount of light emitted from the backlight.