This article is a review of models that capture the magneto-mechanical response of magnetorheological elastomers (MREs) and MRE-based systems. Where available, experimental validations of models are also discussed. The models are categorized as either particle interaction-based, magnetoelastic response-based, magnetoviscoelastic response-based, or models including the effects of environmental conditions and fatigue. Analytical, numerical, finite element, and phenomenological investigations that explore changes in stiffness and damping of anisotropic MREs are reviewed. Phenomenological models of MRE systems used in different applications are also examined.