Background <p>Gun violence represents a major public health concern not only due to direct exposure but also because of its widespread presence in local news and social media. Despite this ubiquity, less is known about how media-based exposure to real-world gun violence relates to mental health outcomes.</p> Methods <p>Using a nationally representative sample of U.S. adults, this cross-sectional study examined the relationship between real-world media gun violence exposure (GVE) and mental health outcomes.</p> Results <p>Findings highlight the association between greater cumulative media gun violence exposure and various mental health outcomes, with greater exposure associated with a greater number of poor mental health days per month (IRR = 1.51; CI, 1.14–1.70) and a higher depression score (IRR = 1.21; CI, 1.07–1.36). Similar trends were found across four types of media GVE (local traditional media, local social media, outside traditional media, and outside social media), with the most associations between outside traditional media and outside social media, and poorer mental health outcomes.</p> Conclusions <p>These findings support existing research suggesting that repeated exposure to gun violence may negatively affect well-being, and that real-world media exposure may also have negative implications. Implications from this study contribute to the growing body of research that identifies the potential harms associated with social media and how incessant real-world violence may negatively affect well-being.</p>