An earthing terminal for mounting on a support rail having a channel section with outwardly turned flanges comprises a yoke of bent sheet metal with a pair of hooks to fit under the flanges, and a metal clamping member with terminals, disposed between respective side parts of the yoke. The yoke has on each side part a lug, the ends of which are bent over to form flanges in which is threaded a clamping screw which contacts the metal member. By means of the clamping screw, the flanges of the support rail can be clamped between the hooks of the yoke, and adjacent parts of the metal member.