Missouri vs. Illinois Non-Compete Laws: Key Differences

The bottom-line difference is this: Illinois has written statutory wage thresholds and notice rules that automatically void non-competes for lower-paid workers, while Missouri has no income floor at all and instead leans on its restrictive-covenant statute, RSMo § 431.202, and a body of case law about reasonableness. Below is a neutral, side-by-side look at how the two states compare across the dimensions that tend to decide real cases.

Are non-competes enforceable in each state?

Both states will enforce non-compete agreements, but both treat them with caution as restraints on a person's ability to earn a living. In Missouri, non-competes are enforceable when they protect a legitimate, recognized business interest and are reasonable in their terms. Missouri courts have made clear that an employer cannot use a covenant simply to block ordinary competition; it must be protecting something the law recognizes, such as trade secrets, confidential information, or established customer relationships. RSMo § 431.202 expressly confirms that reasonable restrictive covenants are not unlawful restraints of trade when they protect those interests.

Illinois likewise enforces non-competes, but only when they survive both a statutory screen and a common-law reasonableness test. The Illinois Freedom to Work Act, codified at 820 ILCS 90 and significantly amended effective in 2022, sets baseline rules that a covenant must clear before a court will even reach the question of reasonableness. Where the statute applies and the worker is eligible to be bound, Illinois courts then ask whether the covenant is supported by a legitimate business interest, judged under a totality-of-the-circumstances test the Illinois Supreme Court described in Reliable Fire Equipment Co. v. Arredondo. In short: Missouri runs the analysis primarily through reasonableness and its statute, while Illinois adds a hard statutory gate in front of that analysis.

Income thresholds and who can be bound

This is the single largest structural difference between the two states. Illinois ties enforceability directly to how much the worker earns. Under 820 ILCS 90, a non-compete is void and unenforceable against an employee whose actual or expected annualized earnings are at or below a statutory threshold — set at roughly $75,000 per year when the amendments took effect, with the figure scheduled to rise over time. Non-solicitation covenants have their own, lower threshold, in the neighborhood of $45,000 per year, and are void below that line. Because both numbers are indexed to step upward on a schedule, you should treat these figures as approximate and confirm the current dollar amounts before relying on them.

Missouri has no comparable income floor. Nothing in RSMo § 431.202 voids a non-compete based on what the employee is paid. Instead, Missouri excludes certain workers by the nature of their job rather than their salary: the statute does not make a non-compete enforceable against an employee who provides only secretarial or clerical services. So in Missouri the gating question is "what does this person do," while in Illinois the gating question is "how much does this person make." A mid-level worker earning $60,000 could potentially be bound in Missouri but would generally be outside the reach of a non-compete in Illinois.

Notice and consideration requirements

Illinois imposes procedural requirements that Missouri does not. Under 820 ILCS 90, an employer must give the employee at least 14 calendar days to review a non-compete or non-solicitation agreement before it takes effect, and must advise the employee in writing to consult with an attorney before signing. These are not optional formalities; failing to provide the required notice and advisement can undermine enforceability. The idea is to make sure workers have a real chance to understand and get advice about what they are agreeing to.

Missouri has no statutory notice-and-advisement rule of this kind. A Missouri non-compete does not become unenforceable simply because the employer handed it over on the first day and asked for a signature on the spot, though as a practical matter giving an employee time to review is still wise.

On consideration — the value the employee must receive in exchange for the promise — both states require it, but they frame it somewhat differently. In Missouri, an offer of initial employment is valid consideration for a covenant signed at hiring, and continued at-will employment can serve as sufficient consideration for a covenant signed after the job has already begun, especially when paired with access to confidential information or training. Illinois courts have been more demanding about consideration that rests on continued employment alone: they often look for roughly two years of continued employment, or some other substantial value such as a bonus or other benefits, before treating continued employment as adequate consideration. So a covenant an employee signs mid-job and then leaves shortly afterward may face a consideration problem in Illinois that it would not face in Missouri.

Reasonableness and blue-penciling

Even after the threshold questions, both states require the covenant itself to be reasonable. Missouri courts weigh three dimensions: the duration of the restriction, its geographic scope, and the range of activity it bars, balancing the employer's legitimate interest against the employee's right to earn a living and the public interest. One-year restrictions are routinely upheld in Missouri, two years is often acceptable when justified, and longer terms draw increasing scrutiny. The territory must match where the employer actually does business or where the employee had customer contact.

Illinois applies a similar reasonableness inquiry under the Reliable Fire totality-of-circumstances framework, asking whether the restraint is no greater than necessary to protect a legitimate business interest, whether it imposes undue hardship on the employee, and whether it injures the public. Factors such as the duration, the geographic reach, and the nature of the protected interest all feed into that assessment, with no single factor controlling.

Where the two states can diverge is what a court does with an overbroad clause. Missouri follows a modification, or "blue-pencil," approach: rather than automatically voiding a covenant that reaches too far, Missouri courts — supported by RSMo § 431.202 — may narrow an unreasonable restriction, for example by shortening its duration or shrinking its geography, and then enforce it as modified. Illinois courts can also reform overbroad covenants, but they tend to be cautious about extensive rewriting and may decline to save an agreement that is so overbroad it suggests the employer was not drafting in good faith. The practical upshot is that an overreaching covenant carries somewhat more all-or-nothing risk for the employer in Illinois than in Missouri.

Trade-secret and non-solicitation overlap

Both states recognize that a non-compete is only one of several tools an employer can use, and that trade-secret protection exists independently. Missouri protects confidential, economically valuable information under the Missouri Uniform Trade Secrets Act regardless of whether a non-compete is enforceable, and a former employee who walks out with customer lists or confidential files can face liability on that basis alone. Illinois has its own trade-secrets statute that operates the same way. In both states, then, even a worker who is outside the reach of a non-compete is not free to misuse a former employer's confidential information.

Non-solicitation covenants are treated as a lighter-touch alternative in both states, but the details differ. Missouri treats an agreement not to solicit a former employer's employees as reasonable when limited to no more than one year, and customer non-solicits are generally easier to enforce than full non-competes because they intrude less on the worker's livelihood. Illinois separates non-solicitation from non-competition in its statute and applies a lower income threshold to non-solicits — meaning a worker who earns too little to be bound by a non-compete may still earn enough to be bound by a valid non-solicitation covenant. For employers on both sides of the river, a narrow non-solicit paired with a strong confidentiality agreement often protects the real interest with less enforceability risk than a broad non-compete.

Key differences at a glance

• Income thresholds: Illinois voids non-competes below an approximate annual income threshold (around $75,000) and non-solicits below a lower threshold (around $45,000), both scheduled to rise — confirm current figures. Missouri has no income floor.
• Who is excluded: Illinois excludes workers by earnings; Missouri excludes only secretarial or clerical employees by job function, not by pay.
• Notice and advisement: Illinois requires at least 14 days to review and a written recommendation to consult an attorney before signing. Missouri imposes no such statutory requirement.
• Consideration: Missouri accepts initial or continued at-will employment as consideration. Illinois courts often look for roughly two years of continued employment or other substantial value.
• Governing law: Missouri non-competes are governed by RSMo § 431.202 and case law; Illinois non-competes are governed by 820 ILCS 90 plus the Reliable Fire reasonableness test.
• Reasonableness: Both require reasonable duration, geography, and scope, but Missouri's blue-pencil practice is generally more forgiving of overbroad drafting than Illinois practice.

Which state's law applies to your non-compete?

Living in one state and working in another raises a real question: whose law governs the agreement? Most well-drafted non-competes contain a governing-law clause naming the state whose rules are meant to apply, and sometimes a forum-selection clause naming where any dispute must be litigated. Courts will often honor a reasonable choice-of-law clause, but a clause is not a guarantee. A court may decline to apply the chosen state's law where doing so would violate a fundamental public policy of the state where the employee actually lives and works — for example, applying out-of-state law to enforce a covenant against a low-paid Illinois worker whom the Illinois statute would protect, or against a Missouri clerical worker the statute exempts.

Because of that, where you physically work, where the employer does business, and what the contract says can all pull in different directions. If your agreement names a state other than where you work, the safest approach is to have it reviewed under both states' law rather than assuming the governing-law clause settles the matter. In a border metro like St. Louis, this overlap is the rule rather than the exception, and small facts — which office you report to, where your customers are, which state's address is on your offer letter — can change the answer.

When to talk to a lawyer

This comparison is general information, not a substitute for advice on your specific agreement. Because Missouri and Illinois apply genuinely different rules — and because the wage thresholds, notice requirements, and choice-of-law questions turn on facts unique to your situation — it is worth getting your agreement reviewed before you sign it, before you leave a job, or as soon as you receive a cease-and-desist letter or threatened lawsuit. A short consultation can tell you which state's law likely governs and whether your covenant is enforceable at all. You can get matched with a Missouri or Illinois attorney who handles non-compete matters to review your specific documents and deadlines.