In this work, acetylation of raw nettle fibers was performed to improve the oil sorption capacity. Raw nettle fibers were acetylated with acetic anhydride using N-Bromosuccinimide (NBS) as a catalyst. Box-Behnken experimental design was used to study the effect of some selected parameters such as reaction time, reaction temperature and catalyst concentration (%) on weight percent gain (WPG) and oil sorption behavior. Highest WPG and oil sorption were achieved at 90 min reaction time, 120 degrees C and 2% catalyst. The oil sorption of acetylated nettle was 23.21 g/g and 18.75 g/g against diesel engine oil and crude oil, respectively. Nettle fibers were also characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis and Scanning electron microscopy. Oil sorption capacity of acetylated nettle were higher than that of commercial polypropylene sorbent. Hence, these acetylated nettle fibers can be used in the place of synthetic sorbents for oil spill cleanup applications.