There is provided a method of boosting a local dimming signal. In the method, it is determined whether or not local dimming signals, which are applied for individually driving light source blocks per frame, satisfy boosting conditions. Then, a predetermined local dimming signal corresponding to at least one of the light source blocks is boosted to a reference luminance value when the local dimming signals continuously satisfy the boosting conditions, and the boosting luminance of the predetermined local dimming signal at the reference luminance value is gradually decreased after a light adaptation time of an observer's eye. When the luminance of light source blocks that are boosted is gradually decreased before the light adaptation time or luminance of light source blocks that will be boosted is gradually increased to the light adaptation time, power consumption required to boost the light source blocks may be decreased.