United States Fish and Wildlife Service v. Sierra Club, Inc., 592 U.S. 261 (2021), was a Supreme Court of the United States case involving whether the use of a Freedom of Information Act (FOIA) request can be used to access documents from a U.S. agency that are protected under the deliberative process privilege exemption, in this specific case, draft biological opinions made and reviewed by the United States Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) prior to a final rulemaking decision by the Environmental Protection Agency (EPA) related to impacts on endangered aquatic species, requested by the Sierra Club.

While both the FWS and NMFS provided much of their documentation in their consultation period with the EPA, they did not provide the 2013 draft biological opinions, asserting these were protected by deliberative process privilege, one of the allowed FOIA exemptions, and previously affirmed by case law in 1975 by NLRB v. Sears, Roebuck & Co. as to protect "documents reflecting advisory opinions, recommendations and deliberations comprising part of a process by which governmental decisions and policies are formulated".

[4][5] The Sierra Club was seeking to obtain these draft opinions of the EPA regarding rules governing underwater structures used to cool industrial equipment.

[6] The Sierra Club sued in the Northern District of California for release of these draft opinions, since they reflected on the state of the proposed 2013 EPA rather than its final 2014 rule.

The district court agreed with the Sierra Club in July 2017 and ordered release of the drafts, which was upheld on appeal by the government by the Ninth Circuit in December 2018.

The agencies petitioned the Supreme Court to hear the case on the question of whether the draft documents were covered under the deliberative process privilege.