The contact stress distributions between adherends and an adhesive and the deformation in single-lap adhesive joints subjected to tensile loads are analyzed as a three-body contact problem using a two-dimensional theory of elasticity. In the numerical calculations, the effects of the ratio of Young＇s moduli of the adherends to that of the adhesive, the adhesive thickness, and the lap length on the contact stress distributions at the inter-faces are examined. As a result, it is found that the stress near the edges of the interfaces increases as Young＇s moduli of the adherends and the adherend thickness decrease. In addition, the contact stress distribution is analyzed by the finite-element method (FEM). Fairly good agreement is seen between the numerical results and the FEM results; however, a difference is seen between the numerical results and the results obtained by other researchers.