- 2018, Springer International Publishing AG, part of Springer Nature. We propose a new class of models for electrorheological fluids. While the standard constitutive relations for electrorheological fluids are based on the assumption that the stress is a function of the symmetric part of the velocity gradient and the intensity of the electric field, we formulate constitutive relations in an implicit way. The stress, the symmetric part of the velocity gradient and the intensity of the electric field are linked via a tensorial implicit equation. The potential benefit of the new class of models is investigated by the analysis of a simple shear flow in a transverse electric field.