This work presents an accurate and efficient numerical tool for geometrically nonlinear thermoelastic analyses of thinโwalled structures. The structure is discretized by an isogeometric solidโshell model with an accurate approximation of geometry and kinematics avoiding the parameterization of finite rotations. An efficient modeling of thermal strains, temperatureโdependent materials and general temperature profiles based on a numerical preโintegration through the shell thickness is proposed. Then, a generalized pathโfollowing method is developed for solving the discrete equations with the temperature amplifier as additional unknown, in order to trace the temperatureโdisplacement nonlinear curve also in case of limit points and unstable paths. A consistent definition of the tangent operators and a mixed integration point strategy give a robust and efficient analysis. Finally, a reduction technique is derived for a quick estimate of the nonlinear thermal buckling point. The reduced model consists of the initial path tangent, the first linearized buckling modes and their second order corrections. Numerical applications are given.