The main objective of this research is to study the reinforcement role of the adhesively bonded patches in the structure. In order to evaluate the mechanical behaviour of the structure reinforced with external patches, a shear lag model was adopted to investigate the load transfer from the host structure to the adhesively bonded patches. Closed-form solutions of the shear stress in the adhesive and longitudinal forces in the reinforcement patch and host structure were obtained. The theoretical predictions were validated with the numerical analysis using the finite element method. The effect of the adhesive on the load transfer was presented through a parametric study.