A collapsible stereoscopic viewer is comprised of a front wall having light-admitting openings therein; a rear wall assembly having coincident viewing apertures therein; top and bottom walls contiguous with the front and rear walls; and, side walls which include continuous extensions for forming a channel proximate the front wall whereby a stereoscopic film strip may be received therein. A film strip holder for retaining and accurately positioning a pair of photographic film strips is also disclosed. Blanks suitable for assemblying both the viewer and film strip holder are similarly described.