A Kerr magneto‐optic apparatus has been used to observe the effects of tensile stress on the domain structure in grain‐oriented 3.25% silicon steel. Unlike the powder pattern technique, the Kerr apparatus reveals the complete surface domain structure without regard to the type of domain wall, and enables observation of the domain structure changes upon application of small stresses. The behavior under stress of a new pattern, termed the ``chevron,'' has been noted.