<p>This paper studies delamination in multilayered inhomogeneous beam structures exhibiting viscoelastic nonlinearity at elevated temperatures. In this regard, a theoretical analysis based on the J-integral is developed. The analysis uses a nonlinear viscoelastic model to model the beam’s mechanical behavior. The model represents a system of a nonlinear dashpot in parallel with a nonlinear spring. A linear dashpot and a linear-elastic spring are also used in the model. Due to material inhomogeneity, the viscoelastic model parameters vary smoothly across the layer thickness. The time-dependent secant modulus is obtained. The effect of temperature is accounted for by adjusting the secant modulus. The J-integral for the delamination crack in the beam is solved by using the corrected secant modulus. The J-integral solution is checked-up by the strain energy release rate. Using the solution, it is found that delamination is influenced by temperature, variations in material parameters along the thickness, and loading conditions on the nonlinear viscoelastic beam.</p>