Adhesively bonded joints are widely used in structures manufactured with composite laminates. Single-lap adhesive joints are the common most used due to their simple geometry and structural efficiency. In this study, a 2D numerical model has been developed in Abaqus/Standard to evaluate the influence of variations in the geometry of the adherends and the adhesive on the mechanical strength of a single-lap joint subjected to uniaxial tensile load, using the Cohesive Zone Model (CZM). Different geometrical configurations of single-lap joints have been studied, such as adherend recessing and chamfering of the adherends and adhesive. The objective is to analyse the effect of these variations with respect to the mechanical strength of the adhesive joint.