A stabilized halogenated butyl rubber composition comprises halogenated butyl rubber, an alkali metal or alkaline earth metal carboxylate, an ether and an oxide or hydroxide of a Group IIA metal as exemplified by halogenated butyl rubber containing both bromine and chlorine stabilized with a composition comprising calcium stearate, polyethoxylated adducts of sorbitol esterified with from 1 to 6 moles of oleic acid and mixtures thereof, and calcium hydroxide.Halogenated butyl rubbers stabilized in the manner disclosed exhibit improved resistance to discoloration upon high temperature exposure, such as during the drying of polymers in the course of manufacture.