<p>This paper addresses the problem of buckling in thin-walled metallic cylindrical shells subjected to a uniform external pressure, which is the critical issue in engineering applications. Previous investigations have often overlooked the potential of fiber-reinforced polymers (FRPs) in enhancing the buckling strength of such shells under an external pressure. The study aims to fill this gap by investigating the effects of FRP strengthening by integrating analytical, numerical, and statistical methods to evaluate the influence of shell length, thickness, and type of composite material on the buckling pressure. It was found that the most significant factor influencing the buckling behavior is the composite type. Using the theory of orthotropic shells for analytical formulations and a full factorial design of their setup, a comprehensive analysis was conducted, which showed that glass-fiber- reinforced polymers (GFRPs) significantly improved the buckling resistance of steel shells. Numerical results validated the analytical predictions with differences ranging from 2.86 to 9.85%. A desirability analysis was also performed to maximize the critical buckling pressure. The results found provide valuable insights into the optimal design of FRP-reinforced cylindrical shells, enhancing their application in such industrial sectors as storage tanks and pipelines.</p>