Social support has long been considered an important factor in influencing the experience of stress and strain at work (e.g. Cohen and Wills, 1985). Yet the effect of union support on stress and strain has been largely neglected. In the present study we explored the role of social support provided by shop stewards as both a predictor of various indicators of strain experienced by their constituents as well as a buffer of stress–strain relations. These hypothesized relations were evaluated using data provided by rank‐and‐file members (N = 112) of a large local union associated with the automotive industry located in the midwestern region of the U.S.A. The results were not generally supportive of the main‐effect model of steward support, but were consistent with the buffering model.