In this paper, a novel semi-analytical model is developed to capture the mode jumping phenomenon in composite and metallic pressurized fuselage panels. The analytical formulation is derived using the Ritz-based approach and the resulting system of nonlinear equations are solved numerically by homotopy methods. Panels with two different aspect ratios and three different types of boundary conditions are investigated. The panels are loaded in two sequential steps. In the first step the panel is loaded by pressure resulting in a primary mode shape. In the second step, the panel is loaded by an in-plane axial compressive load which causes a sudden change in the primary mode shape leading to a mode jumping event. For verification purposes, finite element models are performed using the commercial software Abaqus. It is demonstrated that the semi-analytical model is able to successfully capture the mode jumping phenomenon and predict the corresponding load. It is also shown that, as opposed to the rectangular panels, the mode jumping of square panels is accompanied with a complete loss of stiffness. Furthermore, the mod jumping of the metallic square panels occurs in the plastic range, while the rectangular panels experience this phenomenon in the elastic range.