Abstract: A wallpaper border applicator apparatus includes a base assembly which includes a first longitudinal axis. A link assembly includes a longitudinal proximal end, a transverse intermediate portion, and a longitudinal distal end which includes a second longitudinal axis. The longitudinal proximal end is rotatably connected to the base assembly. A spool-receiver assembly is connected to the longitudinal distal end of the link assembly and is adapted to receive and carry a spool of wallpaper. The first longitudinal axis and the second longitudinal axis are substantially parallel and substantially co-planar. The spool-receiver assembly includes a cup portion, an aperture-containing floor portion, a fence portion which includes a guide slot adapted to guide wallpaper as it is uncoiled from a spool of wallpaper, and a spool shaft supported by the longitudinal distal end of the link assembly and adapted to fit into a hollow core of the spool of wallpaper. A ruler portion is arrayed on the spool shaft.