This paper investigates the full stress–strain response of bauxite residue concrete under uniaxial compression and presents an adapted constitutive model. This study investigates the stress–strain behavior in a series of uniaxial compression experiments and compares to the Popovics, Thorenfeldt et al. and Hoshikuma et al. model predictions. All models accurately predict the pre-peak behavior, showing a very acceptable error rate; however, none of these models adequately predict the post-peak response. A new post-peak stress–strain model is therefore developed in this paper for bauxite residue concrete. The proposed model predictions agreed well with the experimental measurements obtained in this paper for post-peak stress–strain of bauxite residue concrete.