An electrodeless lamp includes an envelope (1) containing a fill of discharge gas, a magnetic core t(7), an induction coil (6) wound around the magnetic core (7), a driver circuit for supplying an electric current to the induction coil (6) to operate the electrodeless lamp, a socket (10) for receiving electrical power supplied to the electrodeless lamp, and a heat conduction means (8,9) thermally coupled to the magnetic core (7) for conducting heat generated in the magnetic core (7) to the ambient atmosphere to dissipate heat therein, or coupled to the socket (10) for conducting heat generated in the magnetic core (7) to the socket to dissipate heat therethrough.