In the present work process-induced residual stress development is described for a 100 × 100 mm pultruded square profile made of glass/polyester. A thermo-chemical model developed in MATLAB is coupled with a mechanical model developed in ABAQUS. The temperature and degree of cure distributions are calculated for three different preheating temperatures. In the mechanical model, a parameter study is examined to investigate the effect of total volumetric shrinkage (V sh) and the coefficient of thermal expansion (CTE) in rubbery state on the residual stresses. The non-uniform internal constraints in the part yield in an internal shear deformation during the process. The transverse shear stress and compressive normal stress levels decrease significantly as compared with the tensile normal stresses with an increase in preheating temperature. The change in V sh and CTE in rubbery state affects the shear stresses and compressive stresses significantly, whereas the tensile stresses are less affected.