The formulation of a family interface elements belonging to the zero-thickness class is briefly described. The formulation is isoparametric and can be applied to 2-D and 3-D analysis. A flexible constitutive law, based on elastoplasticity, describing the mechanical behaviour of the interface is presented. In order to assess the suitability of the elements for the analysis of soil-reinforcement interaction, they are employed in the simulation of a pull-out test in two and three dimensions. It is shown that the performance of the elements can depend strongly on the type of integration rule adopted. The use of integration schemes, such as that of Newton-Cotes, which result in the uncoupling of the degrees of freedom of the element is shown to be very advantegeous. An application to the analysis of a problem involving softening behaviour of the interface is also included.