In law, “shall” means someone has a duty to do something. When a statute, regulation, or contract uses the word, it imposes a binding obligation on the person or entity the sentence is directed at, not a suggestion or a preference. The U.S. Supreme Court has described “shall” as a word that “normally creates an obligation impervious to judicial discretion.”1Justia Law. Lexecon Inc. v. Milberg Weiss Bershad Hynes and Lerach, 523 U.S. 26 (1998) Courts don’t always enforce it as an absolute command, though, and modern drafters increasingly swap it for “must” to avoid the confusion the older word tends to generate.
The Working Definition: “Has a Duty To”
The standard reading of “shall” in legal drafting is “has a duty to.” A statute saying “the employer shall provide written notice within 30 days” means the employer is legally compelled to give that notice. There’s no option to skip it when the timing feels inconvenient.
The practical test is a substitution. Replace “shall” with “has a duty to” and see if the sentence still makes sense. “The landlord has a duty to return the security deposit within 14 days” works cleanly, which tells you “shall” is doing its job in the original. When the substitution produces nonsense, the drafter has probably misused the word.
The American Bar Association applies this same logic in its Model Rules of Professional Conduct. The Scope section explains that provisions “cast in the terms ‘shall’ or ‘shall not'” are imperatives that “define proper conduct for purposes of professional discipline,” while provisions using “may” are permissive and leave the choice to the lawyer.2American Bar Association. Model Rules of Professional Conduct: Preamble and Scope That line between duty and permission is probably the single most important distinction in legal interpretation.
“Shall” vs. “May”
If “shall” means “has a duty to,” “may” means “is allowed to.” A statute saying “the court shall impose a fine” leaves the judge no choice. A statute saying “the court may impose a fine” gives the judge discretion to fine or not. When a single document uses both words, courts treat the distinction as deliberate.
Contracts rely on this contrast constantly. A lease might say the landlord “may” pay overdue utility bills on a tenant’s behalf and that the tenant “shall” reimburse the landlord on demand. The landlord can choose whether to step in; the tenant has no choice about paying the money back. Confusing the two words during drafting can accidentally convert an obligation into an option, which is exactly the kind of ambiguity that produces litigation.
“Shall Not” vs. “May Not”
“Shall not” creates a mandatory prohibition. “The contractor shall not subcontract any portion of the work” is an absolute bar. “May not” is trickier because it can mean either “is not permitted to” or “might not,” depending on context. In careful drafting, “shall not” is the clearer choice when the goal is an outright ban.
When Courts Read “Shall” as Only Directory
Despite the standard rule, courts sometimes read “shall” as “directory,” meaning the action is expected but a failure to perform it exactly as written won’t invalidate everything that follows. Illinois courts have put it plainly: “shall” generally signals a mandatory obligation, but courts sometimes interpret it as directory or permissive depending on what the legislature actually intended.
This question comes up most often with procedural deadlines. Suppose a statute says a government agency “shall” file a report within 60 days, and the agency files on day 65. Does the five-day delay void everything the agency did afterward? Courts look at a few factors:
- Legislative intent: was the deadline a hard cutoff or an expected timeline?
- Spelled-out consequences: if the statute says nothing about what happens when the deadline is missed, courts are more likely to treat it as directory.
- Harm to the other side: if the delay caused no real prejudice, courts lean toward directory rather than voiding the action.
Federal law on IRS summons notices shows how far this can split. The statute says the IRS “shall” give a taxpayer at least 23 days’ notice before examining certain records. One circuit court enforced that as an absolute command and threw out a late notice. Five others took a softer view, excusing late notice when the taxpayer suffered no actual harm. Same word, same statute, opposite outcomes depending on the court.
The False Imperative Problem
Part of the reason “shall” causes so much trouble is that drafters frequently misuse it. Legal writing experts call this the “false imperative,” and it occurs when “shall” appears in a sentence where nobody is actually being commanded to do anything.
Consider: “There shall be a quorum for the committee to do business.” Apply the substitution test. “There has a duty to be a quorum” is nonsense; a quorum can’t bring itself into existence. The drafter wasn’t commanding anyone, just describing a condition. A clearer version: “The committee cannot act without a quorum.”
Another common misuse: “Service shall be made on the parties.” Service has no volition. The sentence should name who actually has to do the serving: “The plaintiff shall serve notice on all parties.” Bryan Garner, whose legal usage dictionary is widely cited by courts, calls “shall” the most misused word in all of legal language and recommends confining it strictly to situations where a duty is being placed on a person or entity capable of carrying it out.
False imperatives create real litigation risk. When a court encounters “shall” in a sentence that doesn’t clearly command anyone, judges have to guess what the drafter meant, and that guessing is what produces the conflicting interpretations.
The Shift Toward “Must”
Because “shall” is so often misused, federal policy now discourages it. The Plain Writing Act of 2010 requires federal agencies to use “clear, concise, well-organized” language in public-facing documents.3GovInfo. Plain Writing Act of 2010, Public Law 111-274 Federal plain language guidelines implementing that mandate direct agencies to use “must” instead of “shall.”4U.S. Office of Personnel Management. Plain Language
The clearest example is the Federal Rules of Civil Procedure. In 2007, the rules were restyled to replace nearly every “shall” with “must,” “may,” or “should,” depending on the intended meaning. The change didn’t alter any legal rights; it just made the language match what the rules already meant. Where the old version said a party “shall” file a response, the new version says the party “must” file it.
Executive Order 12866 requires that regulations be “simple and easy to understand, with the goal of minimizing uncertainty and litigation,” and Executive Order 13563 reinforces plain-language drafting. “Must” is replacing “shall” in new federal work, but “shall” remains embedded in thousands of older statutes and regulations still in force, so you’ll keep encountering it.
How “Shall” Works in Contracts
In statutes, “shall” imposes a duty backed by government enforcement power. In contracts, the picture shifts. When a contract says a party “shall” do something, that language can be read as a promise, meaning a contractual obligation the other side can enforce, or as a condition, meaning something that must happen before the other side’s own obligations kick in. The distinction matters enormously in a dispute.
Picture a crop insurance policy where the farmer “shall” notify the insurer of any damage within 72 hours. Read as a promise, the clause lets the insurer sue the farmer for damages caused by late notice. Read as a condition, the insurer doesn’t have to pay the claim at all when the farmer misses the deadline. Courts have gone both ways depending on how the contract is structured.
Some drafters now use “will” for promises and reserve “shall” for duties; others have dropped “shall” entirely in favor of “must” for obligations and “will” for future events. The conventions are not universal. If you’re signing a contract, the safest approach is to read every “shall” clause as something you’re legally bound to do, and ask questions before signing if the obligation feels unclear.
What Happens If Someone Ignores a “Shall”
The consequences depend on where the word appears. In statutes and regulations, violating a mandatory “shall” can trigger fines, license revocations, or, for serious offenses, criminal penalties. A regulation stating “all facilities shall maintain fire safety records” is not offering advice. An audit that turns up missing records can produce enforcement action.
In contracts, breaching a “shall” clause opens the door to several remedies. The most common is monetary damages, designed to put the non-breaching party in the position they would have been in if the contract had been performed. When money alone isn’t adequate, as with unique property, a court may order specific performance, compelling the breaching party to actually do what they promised. Contracts can also include liquidated damages clauses that set a predetermined amount owed for a specific breach, sparing both sides the cost of proving actual losses.
How severe the fallout gets usually depends on how central the “shall” clause is to the agreement or statute. A minor procedural “shall” that a court treats as directory may carry no penalty for noncompliance. A “shall” that goes to the heart of someone’s legal rights, like the Supreme Court’s ruling in Lexecon that a transfer court “shall” remand cases back to the originating district, gets enforced to the letter.1Justia Law. Lexecon Inc. v. Milberg Weiss Bershad Hynes and Lerach, 523 U.S. 26 (1998) Knowing which kind of “shall” you’re dealing with is the difference between a technicality and serious legal exposure.