Display omitted Oily water treatment has become an urgent need in our daily life because of its harmful potential to the ecological system. In recent years, functional materials with superwetting or superantiwetting property have experienced a rocketing development due to their applications in various areas, including self-cleaning, anti-icing, printing, water collection, liquid transfer, oil/water separation, and so on. In this regard, recent advances in polymer science hold the promise of fine-tuning the composition and morphology for a targeted design to meet the requirements in specific application fields. This review focused on polymeric materials, especially smart polymers, for controllable oil/water separations. Starting from the fundamental theories and criteria related to the separation mechanisms, different stimuli including pH, solvent, ions, chemicals, temperature, photo, electric, pressure, and dual stimuli for triggering smart oil/water separation processes were summarized. Highlights on polymer types, polymer synthesis approaches, separation materials fabrication method, as well as separation performances were present. Current limitations and future perspective were also given. This review aims to offer deep insights into polymer-based interfacial science and provide guidance for the fabrication of smart polymeric surfaces for oily water separation.