The present disclosure provides a light emitting device including a substrate, a conductive layer, first and second reflective layers, a light emitting element, and an encapsulation layer. The conductive layer is disposed on the substrate. The first reflective layer covers the conductive layer and has an opening exposing a portion of the conductive layer. The light emitting element is disposed in the opening and electrically connects to the conductive layer. The second reflective layer is disposed on the first reflective layer and surrounds the light emitting element, and the second reflective layer has an outer diameter. The encapsulation layer covers the light emitting element. There is a height between a highest point of the encapsulation layer and an upper surface of the first reflective layer, and the height is 0.1 to 0.5 times the outer diameter. The present disclosure also provides a backlight and a display panel.