Abstract: An interlocking fastener and fastening arrangement is disclosed which is particularly suited for attaching a fuel tank hanger strap to a supporting structure on the underbody of an automobile. The fastener can be formed as a unitary end portion of the hanger strap and includes a neck portion and a fastening head from which a pair of unitary tabs extend. The fastener is inserted into an opening in a support and the tabs are then inserted into corresponding slots in the support to thereby reduce the risk of inadvertent disconnection when tension is removed from the fastener. Also disclosed is a bracket for interconnecting with the fastener. The bracket has a pair of spaced, protruding ribs, each having a slot therein. The fastener is inserted between the ribs, rotated to align the tabs with the slots, and then pulled backwards to insert the tabs into the slots.