Thermo-mechanical phenomena are inherently related to composite materials, from manufacturing to service applications. Therefore, analytical and numerical models developed to simulate composite structural behaviour must satisfactorily account for thermal effects. Pagano's solutions for 2D and 3D composite problems are usually the base for comparison of the different theories and finite elements developments, even when thermo-mechanical behaviour is assessed. Although a number of papers in the literature use numerical results based on this solution, the formulation accounting for temperature effects is not explicitly presented, nor discussed. The objective of the present paper is to present Pagano's solution equations for a 2D case of a simply supported beam under a constant temperature field. Results obtained with the derived solution are discussed and compared against a 2D solid Finite Element Model (FEM) generated using a commercial software package.