Butyl methacrylate (BMA) was grafted onto kapok fiber using benzoyl peroxide (BPO) as initiator. The structure of the grafted kapok was investigated using Fourier transform infrared spectroscopy and scanning electron microscopy. The results illustrated that BMA was successfully grafted onto the kapok fiber surface. The effects of monomer concentration, temperature and time on the oil absorbency of grafted kapok fiber were investigated. The oil absorbencies of raw kapok, NaClO₂-treated kapok fiber and kapok-g-butyl methacrylate were evaluated and compared. Compared with raw kapok fiber, grafted kapok fiber showed the highest oil absorbency, with the increase percentage of 63.4%, 42.5% and 56.4% for chloroform, toluene and n-hexane, respectively. Furthermore, the as-developed grafted kapok fiber exhibited excellent reusability, and can be utilized as an eco-friendly material for recovering oil released into the surroundings.