This paper describes an eight-node, assumed strain, solid-shell, corotational element for geometrically nonlinear structural analysis. The locally linear kinematics of the element is separated into in-plane (which is further decoupled into membrane and bending), thickness and transverse shear components. This separation allows using any type of membrane quadrilateral formulation for the in-plane response. Assumed strain fields for the three components are constructed using different approaches. The Assumed Natural Deviatoric Strain approach is used for the in-plane response, whereas the Assumed Natural Strain approach is used for the thickness and transverse shear components. A strain enhancement based on Enhanced Assumed Strain concepts is also used for the thickness component. The resulting element passes well-known shell element patch tests and exhibits good performance in a number of challenging benchmark tests. The formulation is extended to the geometric nonlinear regime using an element-independent corotational approach. Some key properties of the corotational kinematic description are discussed. The element is tested in several well-known shell benchmarks and compared with other thin-shell and solid-shell elements available in the literature, as well as with commercial nonlinear FEM codes. Copyright © 2013 John Wiley & Sons, Ltd.