A reinforced plastic pallet comprises a twin sheet deck structure and three twin sheet runner structures which are fused to the underside of the deck to create three parallel spaced-apart footprints, the spacing between them forming one set of forklift openings. The deck is fabricated from two thermoformed plastic sheets which are peripherally joined together. The lower sheet is formed with upwardly extending spacer knobs which are fused to the under surface of the top sheet to further join the two sheets together. A frame of reinforcing beams is encapsulated into the interior space of the upper deck. The runner structures are also of twin sheet construction and some of them contain reinforcing rods. The runner structures, although they have flat footprints, are generally “W” shaped to provide two additional forklift openings at 90° from the primary forklift openings between the runner structures.