In recent years, fiber-reinforced composite materials have been mostly used in engineering applications due to advantage of the ratio of strength to weight. Fiberreinforced laminated composites with an optimum stacking sequences have become critical issue especially for defence and automotive industry. In this study, stacking sequences optimization of laminated composites for maximum buckling load factor has been investigated using genetic algorithm (GA). Symmetrical and balanced laminated composite plates with 48 layers graphite/epoxy are considered for optimization process. The designs of composite plates have been investigated for various in-plane loadings and aspect ratios. Fiber orientation angles are chosen as design variables. The optimum designs obtained have been controlled by Tsai-Wu and maximum stress failure criteria. Furthermore, dispersed designs for specific cases have been converted to conventional designs and the advantages and disadvantages of various designs have been examined in terms of buckling resistance. Finally, buckling behaviors of 48- and 64-layered composite plates have been studied under overloaded conditions. In design process, the increase in the reliability of the optimization has been provided independently using a variety of genetic algorithm parameters. All the results have shown that the loading conditions and dimensions of composite plates are significant in stacking sequences optimization of laminated composite materials in terms of maximum critical buckling load factor. Furthermore, it has been seen that the fiber orientation angles determine which failure modes (buckling or static failure criteria) are critical.