Self-catalyzed living radical polymerization using quaternary ammonium iodide (QAI)-containing monomers is reported. The monomer contains a polymerizable methacrylate or acrylate moiety and QAI as a catalytic moiety at the side chain. Several (functional) methacrylates and acrylates were successfully copolymerized with QAI-containing monomers without additional catalysts, generating QAIcontaining copolymers. The obtained QAI-containing polymers were further used as catalytic macroinitiators, enabling self-catalyzed block polymerizations of various monomers without additional catalysts. This self-catalyzed living radical polymerization was also used to prepare a QAI-containing polymer brush on a solid surface. This technique is attractive for its wide range of amenable monomers and metal-free nature. The obtained QAI-containing polymers may find biomedical and antibacterial applications.