Abstract This work aimed to obtain thermoplastic starch composites (TPS) derived from starch and fibers of babassu coconut. The (TPS) was prepared with 40% plasticizer (glycerol). The fibers underwent chemical treatment of alkalinization and bleaching. SEM images and infrared spectra showed that wax, lignin, and hemicellulose were removed from the fiber surface. SEM images of TPS starch showed a smooth and uniform surface, whereas images of the TPSWF composite (washed fiber) showed voids between the fiber and the TPS. This phenomenon was not observed in the SEM images of the composites TPSAF (alkalized fiber) and TPSBF (bleached fiber). The tensile strength and elastic modulus of the composites were higher than the pure TPS matrix. Concerning elongation, composites underwent less elongation than TPS. The mechanical properties found for the TPSWF and TPSAF composites do not differ. However, the mechanical properties of the TPSBF composite were better than the properties of the other composites.