In studies carried out in THF at −80°C, lithium n-butoxide was found to speed up the initiation and to an even greater extent the rate of propagation in the alkyllithium-initiated polymerization of styrene. Bulky alkoxides were found to slow down the rate of polymerization by slowing both initiation and propagation although initiation was decreased to a greater extent than propagation. Five equivalents of lithium tert-butoxide stopped the initiation completely under these reaction conditions when n-butyllithium was used as an initiator. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1157–1168, 1999