Glass fibre reinforced gypsum (GFRG) wall panel, a composite walling product, is made essentially of formulated gypsum plaster, reinforced with glass fibres. The behaviour of such wall panels under earthquake loading merits investigation. The hollow cores inside the walls can be filled with reinforced concrete to increase the strength and lateral load resistance. The results of experimental test on a full-scale GFRG wall panel, filled with reinforced concrete, and subjected to axial and in-plane reverse cyclic load, are presented in this paper. The experimental specimen is 1.02 m wide and 2.85 m high. Hysteretic behaviour of the wall panel, acting as a shear wall, is discussed. © 2008 Taylor & Francis Group.