AbstractThe stereoregularity of poly(α‐methylstyrene)s prepared by anionic initiators was determined from the peak area of α‐methyl proton absorptions and aromatic C1carbon absorptions. Highly syndiotactic polymers were obtained at 0°C in both toluene and tetrahydrofuran (THF). Sodium, potassium, and cesium naphthalenes gave polymers with the same syndiotacticity in THF. The syndiotacticity of polymers prepared by sodium and potassium naphthalenes as catalyst in both toluene and THF decreased at low temperatures. This behavior is similar to that ofo‐methylstyrene andm‐methylstyrene in THF. The stereoregulation mechanism in the anionic polymerization of α‐methylstyrene is discussed and compared with that of polystyrene and ring substituted