The aim of this research is to develop a two-dimensional closed-form solution for the stress distribution in adhesively bonded step-lap joints under service conditions: temperature variation and mechanical loading. The current proposed analytical model takes into account the simultaneous effects of elevated temperature and applied load on the performance of both adhesives and adherends layers. In order to validate the proposed solution, comparisons are performed between the obtained analytical solutions and numerical results and good correlation is found. The pertinence of the proposed method is highlighted through various examples of bonded structures that clearly showed that some coupling effects between the two directions of the problem have taken place.