The Bureau of Intelligence and Research (INR) is an intelligence agency in the United States Department of State. Its central mission is to provide all-source intelligence and analysis in support of U.S. diplomacy and foreign policy. INR is the oldest civilian element of the U.S. Intelligence Community and among the smallest, with roughly 300 personnel. Though lacking the resources and technology of other U.S. intelligence agencies, it is "one of the most highly regarded" for the quality of its work.

INR is descended from the Research and Analysis Branch (R&A) of the World War II-era Office of Strategic Services (OSS), which was tasked with identifying the strengths and weaknesses of the Axis powers. Widely recognized as the most valuable component of the OSS, upon its dissolution in 1945, R&A assets and personnel were transferred to the State Department, forming the Office of Intelligence Research. INR was reorganized into its current form in 1947.

In addition to supporting the policies and initiatives of the State Department, INR contributes to the President's Daily Briefings (PDB) and serves as the federal government's primary source of foreign public opinion research and analysis. INR is primarily analytical and does not engage in counterintelligence or espionage, instead utilizing intelligence collected by other agencies, Foreign Service reports and open-source materials, such as news media and academic publications. INR reviews and publishes nearly two million reports and produces about 3,500 intelligence assessments annually.^{[citation needed]}

The INR is headed by the assistant secretary of state for intelligence and research reporting directly to the secretary of state and serves as the secretary's primary intelligence advisor. In March 2021, President Joe Biden nominated Brett Holmgren to lead INR.

INR has played a key role in the US intelligence community.

In 1967, the INR played an important role in an internal governmental review of covert operations oversight. In early 1967, in the wake of news reports regarding CIA interference in domestic affairs and efforts to assassinate Castro, the Johnson White House ordered the Justice Department to investigate CIA ties to private voluntary organizations in the US. It was increasingly clear, writes journalist Tim Weiner, that “[t]he mechanisms created to watch over the CIA and to invest its clandestine service with presidential authority were not working.” The INR provided a memo to Deputy Under Secretary of State for Political Affairs Foy D. Kohler dated February 15, 1967. The memo identified several weaknesses in the oversight and management of the CIA’s “5412 activities” (which refers to an NSC Directive 5412/2 of December 28, 1955 authorizing the CIA to conduct foreign covert actions). While concluding the procedures of the 303 Committee “are not too bad except for the shortness of time for staffing” the INR memo went on to point out that some covert activities “lack adequate detail on how certain programs are to be carried out and we lack continuing review of major ongoing programs in the light of changing circumstances.” The memo made a number of recommendations to improve oversight by the 303 Committee and to revisit procedures for the “handling of 5412 activities.” Later that year, INR’s director Thomas L. Hughes made recommendations to revise NSC 5412 in order “to deal more explicitly with the risks, consequences, and alternatives of covert operations” among other reasons. Among the recommended changes to NSC 5412 are the need for the U.S. to maintain plausible deniability for covert actions as well as an acknowledgment that covert actions “carry the serious long-term risk of eroding or negating [legal and social] principles, which are fundamental to the achievement of long-range United States objectives.” Therefore, “United States policy to keep covert operations to an irreducible minimum, and to undertake a covert operation only when it is determined, after careful consideration, that the prospective results (a) are essential to national security or national interests; (b) are of such value as significantly to outweigh the risks, both immediate and long-term; and (c) cannot be effectively obtained in any other way.” (see Memorandum From the Director of the Bureau of Intelligence and Research (Hughes) to the Deputy Under Secretary of State for Political Affairs (Kohler)). Hughes discussed these recommendations with Secretary of State Dean Rusk and Assistant AG Nick Katzenbach on May 5, 1967. However, NSC 5412 was not revised during the Johnson administration.

In May 2004, the National Security Archive released a highly classified review of INR's written analysis of the Vietnam War during the 1960s commissioned in 1969 by then-INR director Thomas L. Hughes. The INR written analysis was a 596 page study examining US decisions made during the Vietnam War. Some notable information within the review included pointing out the INR relied on circumstantial evidence to blame the North Vietnamese for maliciously attacking the US during the Gulf of Tonkin Incident. The review showed that INR had repeatedly warned of the weaknesses of the South Vietnamese Government and of the failing US strategy in Vietnam, and that, despite pressure from the military and Pentagon, INR had portrayed and projected the course of the war more accurately than any other source. That being said, there are instances within the review noting events the INR could not have predicted, one of the most infamous being the Tet Offensive in 1968; "Nothing, however... of the situation led INR to anticipate the scope or nature of the Tet Offensive." Still, the majority of the INR's findings were accurate to the course of the war and highlighted the poor intelligence gathering of the CIA in comparison. An annex within the review was dedicated to critiquing the CIA's decision in intelligence gathering and the conflict the CIA had with the Defense Intelligence Agency.

In July 2004, the United States Senate Select Committee on Intelligence issued a scathing report on prewar intelligence on Iraq. INR was spared the poor performance review that most other intelligence agencies received, and the panel specifically endorsed the dissent that INR inserted into the National Intelligence Estimate of 2002. The bureau was being studied as a positive example as Congress debated how to best reform U.S. intelligence agencies in the wake of the 2003 invasion of Iraq.