Workers regularly report high levels of stress and burnout because of their daily interactions at work. They also tend to seek social support as a mechanism to reduce stress and burnout. Social support buffers the negative effects of stress on health-related outcomes and is inversely associated with burnout and perceived stress. However, recent research has revealed that not all social support is beneficial. Co-rumination, or excessive negative problem talk about an issue, has been linked to increasing levels of stress and burnout. Working adults (N = 447) completed a survey exploring the relationships between social support, co-rumination, stress, and burnout. Two mediation models predicted that co-rumination would suppress the relationships between social support and both burnout and perceived stress. Data supported both partial mediation hypotheses. This study concludes that some social support can be less-than-beneficial, if the content of the supportive transaction focuses on excessive and negative problem talk.