The first organically templated gallium oxalatophosphonate has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. The structure consists of GaO6 octahedra and GaO4 tetrahedra connected by methylphosphonate and bis-bidentate oxalate anions to form anionic sheets in the ab plane with the charge-compensating propylenediammonium cations and water molecules between the sheets. The methyl groups of the phosphonate ligands extend from both sides of the layers into the interlamellar region. Crystal data: monoclinic, space group P2(1)/n (No. 14), a = 8.8514(4) Angstrom, b = 16.3030(7) Angstrom, c = 15,0816(7) Angstrom, beta = 97.539(1)degrees, and Z = 4.