A lens module includes a lens holder, a filter, and a metal support. The lens holder includes a groove and sidewalls surrounding to form the groove. The metal support includes a support plate, heat dissipation plates, and heat transfer plates. At least one first mounting hole is formed on the sidewalls. The support plate comprises a support portion and a connecting portion connecting to each other. The connecting portion connects the support portion and each of the heat transfer plates. An opening is formed on the support portion and passes through the support portion. The filter is located on the support portion and covers the opening. The heat transfer plates are installed in the at least one first mounting hole. The support plate is received in the groove. The heat dissipation plates are located outside the lens holder. The disclosure also provides an electronic device having the lens module.