An LED assembly (10) includes an LED (12) and a lens (16). The lens covers on an outer periphery of the LED. The LED has an encapsulant (125) and an LED chip (121) received in the encapsulant (125) and having a light emitting surface (122). The lens has a light output surface (161) over the light emitting surface. The light output surface defines a plurality of annular, concentric grooves (163). Each groove (163) is cooperatively enclosed by a first groove wall (165) and a second groove wall (166). The first groove wall is a portion of a periphery of an imaginary cone and a conical tip of the imaginary cone is located on the light emitting surface of the LED chip.