Dynamic Kerr-effect and dielectric relaxation studies have been for a poly(methylphenyl siloxane) fluid in the region of its α relaxation process. The relaxations are broader than a single relaxation-time process and we find τ K, r < τ K, d < τ ϵ and β K, r ≅ β K, d < β ϵ , where K, r; K, d and ϵ refer to Kerr-effect rise, decay and dielectric, respectively; τ and β are the relaxation time and the Williams-Watts relaxation parameter, respectively. It is suggested that the observed Kerr-effect relaxation is largely due to the motions of the phenyl group and that a substantial part of this process is due to motions about the bond joining the silicon atom to the aromatic ring.