This chapter examines how the composition of civil and uncivil content in comment threads influences people’s perceptions of news quality. Based on a mixed-design online experiment in the United States, we found that a higher proportion of incivility in comment threads diminished people’s perceptions of news quality. The effects of online incivility vary across obtrusive and unobtrusive issues, referring to issues that individuals had either high or low amounts of direct personal experience with, respectively. Specifically, the proportion of online incivility was found to have larger detrimental effects on news quality perceptions for obtrusive issues than unobtrusive ones. For obtrusive issues, comment threads starting with uncivil content exacerbated the negative effects of online incivility on news quality perceptions; for unobtrusive issues, comment threads ending with online incivility were more harmful for news quality perceptions. We conclude this chapter by discussing the theoretical and practical implications of our findings.