Abstract <p>The development of natural fiber-reinforced composite materials has gained attention due to their sustainability, renewability, lower cost, biodegradability, safety, and health benefits. Many natural fibers, sourced from plants such as banana, sisal, jute, hemp, kenaf, and coir, are favoured over synthetic fibers like nylon and linen in industries such as aerospace, automotive, sports, construction, and food packaging. These fibers are extracted from abundant sources like animals, minerals, and plants. The quality and yield of fibers depend on the extraction methods used. Additionally, various chemical treatments are applied to natural fibers to improve their compatibility with composite materials. This review article explores various methods for extracting natural fibers, potential beneficial chemical treatments, and their characteristics. These approaches aim to tailor natural fibers as reinforcement materials in polymer matrices to create composite materials. The chemical treatments used to produce application-specific fibers, along with their advantages and disadvantages, have been discussed. The article also examines the mechanical, structural, morphological, and thermal properties of these fibers in detail. The article consists of separate sections on how modern artificial intelligence and machine learning tools assist in predicting the mechanical strength, thermal stability, and structural integrity of natural fibers and their composites. The article dedicates a section to the applications of various natural fibers as reinforcements in composite materials. Finally, the research findings are summarized to provide guidelines for selecting commercially viable natural fibers suitable for composite materials.</p> Clinical trial registration <p>This study does not involve any clinical trials on human participants; hence, clinical trial registration is not applicable.</p> Graphical abstract <p></p>