AbstractResearchers compare natural hemp fibers with synthetic fibers because of their distinct physical and mechanical properties, which have been well established over time. Hemp fibers are a versatile type of plant fiber commonly used in structural composites and have shown promise in various applications which include packaging, construction, and automotive parts. However, designing hemp‐based composite components presents challenges due to factors related to the plant's origin, growth conditions, age, stem position, separation methods, and the irregularity of fiber cross‐sections. This review aims to provide a comprehensive analysis of research on the performance of hemp fibers and their composites concerning moisture and water absorption. It reviews and analyzes important research on the water and moisture absorption properties of hemp fibers. The article also explains the critical properties of hemp fibers, the various factors affecting these properties, the role of hemp fibers in reinforcement composites, and how relative humidity and swelling characteristics impact hemp fiber composite components. Additionally, it highlights potential areas for future research.Highlights Effects of moisture on hemp fiber's structural properties. Mechanisms of water and moisture absorption in hemp fibers. Impact of moisture on hemp fiber reinforced composites. Key factors in selecting matrices for hemp fiber composites. Future prospects for hemp fiber composites in various applications.