Abstract: A clip is disclosed for retaining an insulation panel or the like to a planar surface. The insulation panel has opposite edges provided with a tongue and groove formation for matingly interlocking with adjacent like panels. The clip comprises a piece of sheet material having a base adapted to lie flush on the planar surface upon which the insulation panel is to be mounted. The base is adapted to be secured to the planar surface. The clip has an interlock portion adapted to follow the contours of the joint between adjacent tongue and groove interlocks. The interlock portion terminates within the thickness of the insulation panel. The interlocking member has a slot extending substantially perpendicular to said base portion for receiving a fin member.