Abstract: The growing demand for sustainable construction materials has intensified interest in the use of natural fibers as reinforcement in concrete. This study presents a critical review of recent research on natural fiber–reinforced concrete (NFRC), with particular emphasis on abaca, bamboo, banana, coconut coir, and jute fibers. The review synthesizes experimental findings on the effects of these fibers on the physical, mechanical, and selected durability-related properties of concrete. Results from the literature indicate that natural fibers can significantly enhance tensile strength, flexural strength, toughness, ductility, and post-cracking behavior of concrete when incorporated at optimal dosages, typically at low volume fractions. Fibers such as abaca and jute show notable improvements in strength characteristics, while banana and coconut coir fibers primarily contribute to increased energy absorption and impact resistance. However, reductions in workability and inconsistent compressive strength performance are commonly reported, due to the hydrophilic nature, variability, and dispersion challenges of natural fibers. The review also highlights gaps in current research, particularly concerning long-term durability, fiber degradation in alkaline environments, and standardized mix design methodologies. Overall, the findings demonstrate that natural fibers offer a viable and environmentally friendly alternative to synthetic and steel fibers for selected structural and non-structural applications. Their use supports sustainability goals by reducing cement consumption, utilizing agricultural waste, and lowering the environmental footprint of concrete, while emphasizing the need for further research to enable wider engineering implementation.