Several works have been reported on the corrosion inhibition of different metals in various corrosive environments. Initially attention was centered on organic compounds but later focused on green inhibitors. Green inhibitors include nontoxic, eco-friendly polymers and natural inhibitors. In recent years, there has been increased emphasis on applications of polymers, copolymers, grafted polymers, and polymer composites as green corrosion inhibitors. The prime controlling factors influencing the corrosion inhibitive performance of polymeric compounds on the corrosion of metals in various corrosive environments are discussed in this review. The superior performance of a polymeric corrosion inhibitor is due to its larger size and greater number of functional anchoring groups. Through the anchoring groups the polymers easily get adsorbed on the metal surface and cover considerably more surface than the corresponding monomers. The main factors influencing the corrosion mitigating properties of the polymers are molecular size, weight, composition, and nature of the anchoring groups. The solution pH, concentration, exposure time, and temperature also find their role in inhibition performance. In this review, we have tried to cover various types of polymeric corrosion inhibitors for iron and its alloys.