This study focused on the role played by social support on the job from coworkers and supervisor in facilitating newcomer adjustment and in mitigating the effects of unmet-expectations stress. The literature on social support indicates that it has three kinds of impacts on stress and subsequent outcomes: a main effect on outcomes, a main effect on perceived stress, and a moderating effect on outcomes. The present study investigated the interrelationships of stress, social support, and outcomes at work, using a sample of newly graduated nurses in their first six months on full-time hospital jobs. A longitudinal design employing three waves of data collection was used. Social support was found to have important main effects in reducing the level of unmet-expectations stress and facilitating positive adjustment outcomes among newcomers.