Small diameter poly(phenylene ether) fibers can be consistently formed from a composition comprising specific amounts of a poly(phenylene ether), a processing aid, and optionally a poly(alkenyl aromatic). The processing aid can be LLDPE, a petroleum resin, or combinations thereof. The processing aid can optionally further comprise a phosphite or phosphonate. Flame retardants are minimized or excluded from the composition. The fibers can be melt spun without entanglement or breakage, and this improved processability enables small diameter fibers to be formed. The resulting fibers can be used in reinforcing structures for printed circuit boards.