Carbon emissions and the global energy crisis rise to prominence as a consequence of the industrial demand for lightweight, high-performance materials. The application of lasers in the process of polymer welding enables the fabrication of complex, lightweight structures as well as hybrid structures. Despite the substantial progress in laser welding technology, the widespread implementation and utilization of this method persistently confront numerous challenges and constraints. Therefore, there is an urgent need for an in-depth review of the laser welding of polymers, including their properties and recent advancements. The present research paper offers a comprehensive examination of the fundamentals of laser welding polymers, the most important laser welding parameters, a variety of polymer types and their engineering applications, as well as the benefits and drawbacks of joining them with or without metallic alloys. In addition, the paper elucidates the various additives that are employed in laser welding and the notable progress that has been made in the area of joining polymers to one another and metals to metal alloys.