The major questions doctrine is a principle of statutory interpretation in United States administrative law under which, pursuant to recent Supreme Court precedent, courts have held that questions of major political or economic significance may not be delegated by Congress to executive agencies absent sufficiently clear and explicit authorization. It functions as a canon to limit broad assertions of implied powers, effectively reinforcing the role of legislative power.

The doctrine was articulated as a paradigm in FDA v. Brown & Williamson Tobacco Corp. (2000), which advised "common sense" in assessing whether Congress intended to delegate broad regulatory powers. The phrase "major questions" first appeared in legal scholarship in a 1986 article by Stephen Breyer, and it was first referred to as a "doctrine" in 2008, with the name "major questions doctrine" entering the scholarly mainstream by around 2013. It gained increasing support of conservative legal organizations amid the deregulatory agenda of the first presidency of Donald Trump. Brett Kavanaugh used the term "major rules doctrine" in a 2017 United States courts of appeals dissent, and described it as a know-it-when-you-see-it principle in his Supreme Court confirmation hearing later that year.

It was applied in Utility Air Regulatory Group v. EPA (2014) and King v. Burwell (2015), with Chief Justice John Roberts writing for the majority in the latter. The Court first explicitly called it the "major questions doctrine" in West Virginia v. EPA (2022), where it held that agencies must point to "clear congressional authorization" for the power asserted in "extraordinary cases". The Court characterized the doctrine as an identifiable body of case law addressing agencies repeatedly asserting transformative authority unsupported by legislative mandate.

Scholars distinguish between narrow forms of the doctrine, assessing reasonableness of interpretation as a Chevron deference limitation, and broader forms like the clear statement rule. The doctrine has been variously criticized for promotion of "judicial self-aggrandizement" and inconsistency with textualism, originalism, and norms of statutory interpretation. Mila Sohoni wrote that it portends to transform judicial review of agency action.

The narrower version of the major questions doctrine was as an exception to Chevron deference. Under Chevron v. Natural Resources Defense Council (1984), courts deferred to reasonable agency interpretations of ambiguous provisions:

First, always, is the question whether Congress has directly spoken to the precise question at issue. If the intent of Congress is clear, that is the end of the matter; for the court, as well as the agency, must give effect to the unambiguously expressed intent of Congress. If, however, the court determines Congress has not directly addressed the precise question at issue, the court does not simply impose its own construction on the statute [...] Rather, if the statute is silent or ambiguous with respect to the specific issue, the question for the court is whether the agency's answer is based on a permissible construction of the statute.

Chevron treated Congressional silence or ambiguity in a statute as an implicit delegation of authority to the agency entrusted to implement the statute. During the Roberts Court, the conservative majority became increasingly skeptical of Chevron deference and eventually overruled it in Loper Bright Enterprises v. Raimondo (2024), leaving this aspect of the major questions doctrine superfluous.

Since MCI Telecommunications Corp. v. AT&T Co. (1994), the Supreme Court occasionally declined to give agencies deference in several cases where it did not think Congress would grant sweeping authority in seemingly insignificant provisions.