In this work, the effectiveness of poly(acrylamide-co-N,N-diethylacrylamide-co-n-butylstyrene), designated as TTF which exhibits a thermothickening behavior, was examined as a novel flocculant for oily wastewater treatment. The effects of flocculant concentration, temperature, and electrolyte on TTF flocculation performance were examined in comparison with cationic polyacrylamide (CPAM). TTF exhibited a lower critical solution temperature (LCST) of 53?C when the monomer feed molar ratio of acrylamide/N,N?-diethyl acrylamide/n-butylstyrene: 73/26/1 was used. Moreover, increasing the concentration of NaCl and CaCl2 adversely reduced the LCST of TTF. Furthermore, treatment with TTF proved excellent performance in removing oil and suspended solid than CPAM in all conditions investigated.