Abstract Automated fiber placement (AFP) is one of the recently developed robot-assisted composite manufacturing techniques. Steering fibers along optimal curvilinear paths enables tailoring the multifunctional properties of laminated composites to fully exploit all potentials of composite materials. This type of advanced composites, called variable stiffness laminates, can optimize the structural performance of composites. In this paper, we aim at developing a novel semi-analytical methodology to conduct hygro-thermo-mechanical analysis on thin to relatively-thick fiber-steered composite panels. The principle of minimum total potential energy, and Layer-wise method are employed to explore the effects of fiber steering on the hygro-thermal and mechanical buckling loads, natural frequency, bending deformation, and stress distributions of conical and cylindrical panels as well as circular plates made by AFP technology without considering manufacturing defects. The numerical results show that the buckling loads and fundamental frequencies of composite conical panels could be improved up to 57% and 44%, respectively, by using a constant curvature fiber-steered lay-up instead of a corresponding quasi-isotropic composite.