A light-emitting diode (LED) lens for covering a LED light source includes a lens body made of a transparent material. The lens body has a light-exit surface and a light-entrance portion. The light-exit surface is configured along the longitudinal direction into a pair of convex surface areas and a concave surface area interconnecting the convex surface areas. The concave surface area has minimum dimensions smaller than maximum dimensions of each of the convex surface areas along first and second transverse directions. The light-entrance portion is adapted for receiving the LED light source, and has a light-incident surface. The light-incident surface has a pair of end portions opposite to each other along the longitudinal direction and extending inclinedly away from the light-exit surface and away from each other.