The local buckling and buckling capacity of the stiffened panel is increased with the raising depth of stiffeners; consequently, the panel local buckling can be prevented by maintaining the optimum stiffener depth for the design and use in maximum load bearing capacity of the lightweight structures. This study deals with numerical analysis of the hat-stiffened panel under compression load with the varying parameters of hat-stiffener, three types of Ply configuration, and panel aspect ratio by using FE tool ABAQUS. Using a strain gauge data-logger system, an experimental investigation is also performed on a panel with the boundary conditions of clamped-in-loaded edges and unrestricted two unloaded edges. Load–displacement curve of the experimental results is in good agreement with FE analysis results obtained from ABAQUS for the buckling and collapse of the panel. The buckling load and deformed shapes of the composite panel are analyzed here for the design of the lightweight compressive member. A database is prepared for buckling study on the stiffened panel with varying depth and spacing of stiffeners, panel orthotropy ratio, plies configuration, and aspect ratio. Based on the studies, a few crucial factors that affect buckling behavior are found, and general guidelines are provided for hat-stiffened panels with three different ply configurations.