Constructing polymeric toroids with a uniform, tunable size is challenging. Reported herein is the formation of uniform toroids from poly(γ‐benzyl‐l‐glutamate)‐graft‐poly(ethylene glycol) (PBLG‐g‐PEG) graft copolymers by a two‐step self‐assembly process. In the first step, uniform rodlike micelles are prepared by dialyzing the polymer dissolved in tetrahydrofuran (THF)/N,N′‐dimethylformamide (DMF) against water. With the addition of THF in the second step, the rodlike micelles curve and then close end‐to‐end to form uniform toroids, which resemble a cyclization reaction. Rodlike micelles, self‐assembled from polypeptide graft copolymers with rigid backbones, can exclusively close end‐to‐end to form toroids under solvent and temperature stimuli. This transformation resembles a cyclization reaction.