Monopiles have been by far the most common support structure for offshore turbines. They have always been an appropriate solution for complex site conditions. Design of monopiles is usually based on the use of nonlinear p-y curve. These curves are primordially based on the use of simple constitutive models for soil, such as Tresca criterion. Since soil behavior is highly non-linear and very complex, fundamental features of soil such as anisotropy, creep, or destructuration have to be taken into consideration. Accordingly, it is necessary to consider more complex soil behavior constitutive models. This work aims to explain, via FEM simulations, the influence of different constitutive laws for soil, on the laterally loaded pile responses. Tresca, Mohr-Coulomb criteria and Modified Cam-Clay model have been compared and their effect on p-y curve is analyzed.