Various embodiments may relate to a lens for a lighting assembly. The lens includes a bottom surface, a top surface and a side surface joining the bottom surface and the top surface. The bottom surface includes an incident surface, and the top surface includes an emergent surface, wherein the side surface includes a first side surface part and a second side surface part arranged in sequence in a direction from the top surface to the bottom surface, and the first side surface part and the second side surface part are defined by different curved surfaces and both are configured as reflection surfaces.