In this study, Calotropis gigantea fiber was evaluated as an oil-absorbing material for removal of oil from water. Preliminary experiments show that water droplets can roll off the fiber surface, while oil droplets can spread over the surface completely, indicating its excellent hydrophobic–oleophilic properties. Further studies reveal that this fiber exhibits fast absorption kinetics and high absorption capacity between 22.6 and 47.6 g/g for various oils and organic liquids, and can efficiently recover the oil spills on the surface or below the water. Moreover, this fiber can be used as a recyclable absorbent for highly efficient oil–water separation.