Disclosed are flame retardant compositions comprised of (a) brominated anionic styrenic polymer, and (b) at least one polybrominated alpha-omega diphenylalkane having a total of at least 6 bromine atoms directly bonded to the phenyl rings and in the range of 1 to 6 carbon atoms in the alkylene group disposed between the phenyl groups, and specified flame retarded polymer compositions with which have been blended (a) and (b) individually or in combination.