A light-weight gypsum-based composition is provided which is particularly suitable for use in the production of wall panels. The composition comprises: (i) gypsum; (ii) glass, ceramic or polymer microspheres; and (iii) a coupling agent preferably selected from a silane or metal coupling agent. The resultant panel has good strength properties and has good performance with respect to nailability and cutability. Further, the paper backing commonly used on traditional commercial drywall panels can be optionally eliminated. The composition can also be cast into thicker products. A lightweight wall panel material is provided.