Politically tumultuous times have created a problematic space for teachers who include the news in their classrooms. Few studies have explored perceptions of news credibility among secondary social studies teachers, the educators most likely to regularly incorporate news media into their classrooms. We investigated teachers' operational definitions of credibility and the relationships between political ideology and assessments of news source credibility. Most teachers in this study used either static or dynamic definitions to describe news media sources' credibility. Further, teachers' conceptualizations of credibility and perceived ideological differences with news sources were associated with how credible teachers found each source. These results indicate potential inconsistencies in how news credibility is defined and possible political bias in which sources social studies teachers use as exemplars of credibility.