The paper presents a sand production model for a deforming oil sand matrix. The deformability of the oil sand matrix is an important issue given that in situ and well pumping induced stresses impact on the susceptibility of the oil sand to produce, sand. The sand production model is formulated in a consistent, manner within the framework of mixture theory with porosity as one of the main field state variables. The latter is split into two parts: one related to volume changes as a result of erosion in the, oil sand matrix, and the other one due to deformations in the matrix subjected to a stress field. The coupling of the erosion model to a stress model is made through bulk volumetric strains. Also, the erosion constitutive law is intimately tied with material strengths that enter the stress model. Finally, some numerical examples of sand production restricted to a rigid matrix are given to illustrate the theory, pending the completion of the finite element implementation of a coupled stress-erosional model.