In legal writing, the word “may” grants permission or discretion: it tells you an actor is authorized to do something but is not required to do it. That is the settled legal definition of may across statutes, regulations, contracts, and treaties. When a statute says a court “may award costs,” the court can but need not. When a contract says a party “may terminate,” that party has the option, not the duty. The single syllable decides whether a provision creates a right, an obligation, or a choice.
What “May” Means in Legal Writing
Leading drafting authorities say the same thing in slightly different words. Bryan Garner defines “may” as “has discretion to; is permitted to.” Kenneth Adams, writing on contract drafting, treats it as “has discretion to, is permitted to, or is authorized to.” Reed Dickerson’s foundational drafting text puts the rule in a single line: “To create discretionary authority, say ‘may.'”1University of Texas School of Law. May vs. Reserves the Right To Cornell’s Legal Information Institute defines “may” as an expression of “possibility, permission, liberty, or power” that “ordinarily implies discretion.”2Legal Information Institute. May
Courts have treated the word the same way for a long time. The Iowa Supreme Court in Bechtel v. Board of Supervisors of Winnebago County (1933) stated that “the primary or ordinary meaning of the word ‘may’ is undoubtedly permissive and discretionary.”3Michigan Bar Journal. May for Granting Discretion Nebraska’s statutory code puts the presumption in black-letter terms: “When the word may appears, permissive or discretionary action is presumed.”4Nebraska Legislature. Nebraska Revised Statute 49-802
The U.S. Supreme Court has stated the rule in strong terms. In Biden v. Texas (2022), Chief Justice John Roberts wrote that “‘May’ does not just suggest discretion, it ‘clearly connotes’ it,” calling the word “expressly discretionary,” especially when a statute pairs it with “shall.” Earlier cases built the same point: Lopez v. Davis (2001) held that “may” signals “the authority, but not the duty” to act; Jama v. Immigration and Customs Enforcement (2005) drew the “may” versus “shall” contrast; and Opati v. Republic of Sudan (2020) reaffirmed that “may” clearly connotes discretion.3Michigan Bar Journal. May for Granting Discretion
How “May” Differs From “Shall” and “Must”
The contrast is the backbone of legal drafting. “May” grants authority. “Shall” and “must” impose a duty. Justice Antonin Scalia and Bryan Garner framed it as a canon of interpretation in Reading Law: “Mandatory words impose a duty; permissive words grant discretion.”3Michigan Bar Journal. May for Granting Discretion
Courts enforce the distinction most firmly when both words appear in the same statute. A California appellate court in RSL Funding, LLC v. Alford held that “settled principles of statutory construction” direct courts to read “may” as permissive and “shall” as mandatory, particularly when the legislature used both in a single enactment.2Legal Information Institute. May The reasoning is simple: if the drafter chose different words, the drafter meant different things.
“Must” has gained ground on “shall” in modern drafting because “shall” became unreliable. Legal writing scholars, including Richard Wydick and Joseph Kimble, documented that “shall” had been so widely misused that it sometimes meant “must,” sometimes “may,” and sometimes just signaled future tense.5Illinois State Bar Association. Must vs. Shall Under the cleaned-up vocabulary the reformers propose, the four options are tidy:
- “must” means “is required to”
- “must not” means “is required not to”
- “may” means “has discretion to”
- “may not” means “is not permitted to”5Illinois State Bar Association. Must vs. Shall
Drafters who use “shall” to grant a right, as in “the lender shall have the right to accelerate,” are generally considered to be writing poorly. The construction muddies the line between obligation and discretion and can weaken enforceable duties elsewhere in the same document.3Michigan Bar Journal. May for Granting Discretion
When Courts Read “May” as Mandatory
The presumption of discretion is strong but not absolute. Cornell’s LII notes that “may” can be read as mandatory “if necessary to give effect to the clear intention of the legislature.”2Legal Information Institute. May The U.S. Supreme Court in Cortez Byrd Chips, Inc. v. Bill Harbert Construction Co. (2000) acknowledged that the presumption of discretion can be “defeated by indications of legislative intent to the contrary or by obvious inferences from the structure and purpose of the statute.”6Justia. Cortez Byrd Chips, Inc. v. Bill Harbert Construction Co.
Those cases are the exception, and courts resist the move. The Michigan Court of Appeals in Association of Home Help Care Agencies v. Department of Health and Human Services rejected an argument that “may” was mandatory and held that the word “typically reflects a permissive condition, entrusting a particular choice to a party’s discretion.”3Michigan Bar Journal. May for Granting Discretion The Supreme Court of Ohio in TWISM Enterprises v. State Board of Registration for Professional Engineers and Surveyors (2022) refused to stretch a statute saying courts “may” consider an agency’s interpretation into a rule of mandatory deference, writing that “what a court may not do is outsource the interpretive project to a coordinate branch of government.”7Supreme Court of Ohio. TWISM Ents., L.L.C. v. State Bd. of Registration for Professional Engineers and Surveyors
The practical point: the party arguing that “may” means “must” is fighting the plain text and carries a heavy burden.
The “May Not” Problem
One corner of the word’s usage causes real confusion. In everyday English, “you may not” usually means “you are not permitted to.” But a careful reader can argue it means “you might not” or even “you may decline to.” Canada’s Department of Justice considers the ambiguity serious enough that it bars the use of “may not” and “no person may” to create prohibitions in new legislative drafting, directing drafters to write “must not” or “prohibited” instead.8Department of Justice Canada. Legistics – Must and May Kenneth Adams gives the same advice for contracts: restate the prohibition explicitly rather than relying on “may not” to carry the weight of “shall not.”9Adams on Contract Drafting. Shall Not Unless Versus May Only If
If you encounter “may not” in a document that matters, read it in context and look at how the drafter uses “may” and “shall” elsewhere. Consistent usage across the document is the best clue to what the drafter intended.
“May” in Contracts
In contracts, “may” does the same work it does in statutes. A Texas court in Nalle v. Taco Bell Corp. read “may” in a contract as expressing “possibility, permission, liberty, or power.”2Legal Information Institute. May Georgetown Law’s drafting guidance notes that courts typically treat “may” in contracts as “permissive or discretionary unless the context indicates otherwise.”10Georgetown Law. Tips for Achieving Clarity in Contract Drafting
A clause saying one party “may” terminate on thirty days’ notice gives that party an option, not a duty. A clause saying the lender “may” accelerate the loan on default gives the lender a choice. The counter-party cannot force the holder of a “may” right to use it.
One source of ambiguity worth flagging: “may” also has a non-legal meaning of “possibly will” or “might.” In transactional documents that can blur whether the drafter is granting authority or describing a future possibility. The common fix is to use “may” only for discretion and “might” for possibility, or to define “may” at the start of the document as “is authorized to.”1University of Texas School of Law. May vs. Reserves the Right To
“May” in Treaties and International Instruments
The permissive meaning carries into international law, where it signals optional rather than binding language. A Swiss federal practice guide on international treaties advises reserving “may” for non-binding instruments such as memoranda of understanding and letters of intent, while “shall” and “undertakes” are used in legally binding treaties creating specific commitments.11Swiss Federal Department of Foreign Affairs. Practice Guide to International Treaties The Vienna Convention on the Law of Treaties (1969) uses “may” throughout to describe options available to states; Article 19, for example, provides that a state “may” formulate a reservation when signing or ratifying a treaty, unless the treaty prohibits it or the reservation is incompatible with the treaty’s object and purpose.12United Nations International Law Commission. Vienna Convention on the Law of Treaties
Reading “May” in a Statute or Contract You Care About
When you run into “may” in a document that affects your rights, start with the presumption that it grants discretion. A zoning board that “may” grant a conditional use permit can approve or deny the application. A court that “may” award attorney’s fees can decide either way. A party that “may” terminate on notice has the option and nothing more. If someone tells you a “may” provision requires action, ask what in the statute’s text, structure, or legislative history overcomes the ordinary meaning. In most cases, the answer is nothing, and the word means exactly what it says.