Abstract: A thermally insulated framing system for storefronts and the like includes inner and outer framing elements connected by a combination twist-in/snap-on insulating clip. The base of the clip is twist-lockable into a locking channel on one frame member, and compressible ridges on the lower face of the base wedge the base securely within the locking channel. A pair of legs at the other end of the clip are snap-fittable onto a locking flange formed on the other frame member. By providing a plurality of pairs of retaining grooves on the locking flange, the clip can be locked into any one of a plurality of locking positions relative to the locking flange, enabling the framing system to accommodate glazing panels of different thicknesses.