Supramolecular polymers, originating from the interplay between polymer science and supramolecular chemistry, have attracted increasing interest in the scientific and industrial communities. To date, most supramolecular polymers are constructed in homogeneous solutions. Supramolecular polymerization normally takes place spontaneously in solutions, thus creating challenges in fabricating supramolecular polymers in a controlled manner. By combining supramolecular polymerization and interfacial polymerization, supramolecular polymerization can be transferred from homogeneous solutions to interfaces, which allows for the controlled production of supramolecular polymers. In this Perspective, we will summarize recent progress and the advantages in supramolecular polymerization at solid-liquid and liquid-liquid interfaces. Meanwhile, current challenges and opportunities in the field of supramolecular polymerization at interfaces are proposed and discussed. It is anticipated that this Perspective will inspire supramolecular polymerization at interfaces and facilitate the construction of supramolecular polymeric materials with diverse architectures and tailor-made functions.