Conservatives have adopted effective legal mobilization strategies in pursuit of their policy goals, but their legal mobilization efforts in the area of climate change politics are understudied. This paper explores the legal mobilization tactics of climate denialist groups, such as the industry-backed American Tradition Institute and the Free Market Environmental Law Clinic. These groups are increasingly using Freedom of Information Act (FOIA) requests to establish evidence of organized political activity by public university researchers who study the dynamics of climate change. This manuscript adds to the legal mobilization literature in three ways. First, this paper traces the origin of these climate denialist groups to the broader conservative legal movement of the 1970s that sought to challenge the dominance of legal liberalism in law schools, public interest groups, the judiciary, and other elite-dominated institutions, such as universities. Second, this manuscript uses the high profile case of Virginia Attorney General Ken Cuccinelli’s and the American Tradition Institute’s FOIA campaign against climate researcher Michael Mann to demonstrate how the legal mobilization tactics of climate denialist groups caused the American Association of University Professors (AAUP), the Union of Concerned Scientists (UCS), and the Climate Science Legal Defense Fund (CSLDF) to successfully countermobilize with their own legal campaign in support of the First Amendment rights of faculty. Finally, this manuscript provides the first empirical evidence of the effect of climate denialist FOIA suits on the activities of university researchers. Through personal interviews with researchers who have been asked to produce information under a FOIA request or state equivalent, I find overwhelming evidence that these requests do not alter the ways that they communicate research findings via email, but that they report initial negative experiences after learning of these requests and their means of communication are altered in the aftermath of these requests.