Exclusivity Clauses vs. Right-to-Work Laws: Can Your Employer Contractually Ban Moonlighting?
Someone forwarded me their employment contract last month with one line highlighted in yellow. It said they could not, during the term of employment, engage in any other business, occupation, or paid activity whatsoever without prior written consent.
Their question was reasonable. They freelance on weekends. Different industry, different clients, zero overlap. Was this thing actually enforceable, or was it corporate throat-clearing?
The honest answer is that it depends on four things, and only one of them is what the contract says.
First, a term that trips almost everybody
Let’s clear up the phrase in the title, because it causes more confusion than any other bit of employment vocabulary.
In the United States, “right-to-work” does not mean what it sounds like. It has nothing to do with your right to hold a job, take a second job, or resist a restrictive contract. It refers narrowly to state laws prohibiting union security agreements, meaning you cannot be required to join a union or pay dues as a condition of employment. That’s it. Roughly half the states have such laws and they are irrelevant to moonlighting.
Elsewhere, the same phrase means something closer to its plain reading: a recognized right to earn a living, which appears in various constitutions and in international instruments including those maintained by the International Labour Organization. That version is genuinely relevant here, because it’s the principle courts reach for when they decide an employer has overreached.
So when someone tells you a right-to-work state protects your side hustle, they’ve merged two unrelated ideas. Worth knowing before you rely on it.
What an exclusivity clause is actually protecting
Employers write these clauses for four distinct reasons, and courts treat them very differently depending on which reason applies.
Competitive harm is the strongest. You work for a logistics firm and you’re also consulting for a rival. That isn’t moonlighting, that’s a conflict, and no legal system I’m aware of protects it.
Confidentiality risk is nearly as strong. Even in a non-competing role, if the second job creates a realistic pathway for protected information to leak, the employer has a legitimate interest.
Capacity is weaker but real. Safety-critical roles in particular carry genuine fatigue rules, and pilots, surgeons, and heavy-vehicle drivers face restrictions that have nothing to do with employer preference.
And then there’s the fourth reason, which is the most common and the least defensible: the employer would simply prefer your full attention, forever, including on Sunday. This is the category that blanket clauses are usually written to capture, and it’s the category that holds up worst.
The tests that actually decide it
Common law systems tend to converge on reasonableness. A restriction has to protect a legitimate business interest, go no further than necessary, and not be contrary to public policy. A clause banning all outside activity of any kind fails the second limb almost by definition, because a total ban is broader than any legitimate interest requires.
The UK approach is instructive. Acas guidance on contracts and working hours reflects a position where an employer can restrict second jobs that create conflict, breach working-time limits, or damage the business, but cannot simply forbid outside work as a matter of principle. Since 2024, UK law has also voided exclusivity clauses outright for lower-paid workers, on the straightforward reasoning that you cannot restrict someone to one employer while paying them too little to live on.
In the US, the picture is messier and jurisdictional. The Federal Trade Commission’s rulemaking on non-compete clauses attracted enormous attention and then ran into litigation, leaving the field largely to state law, where California, Minnesota, Oklahoma, and North Dakota take a notably hostile view of post-employment restraints. During employment, though, the duty of loyalty gives US employers more room than most people assume.
The Gulf presents a different structure again, because employment there is tied to sponsorship and work permits rather than to contract alone. That means the question isn’t only whether your employer permits a second job, but whether the regulatory framework does. UAE labour law has moved considerably on this and now accommodates multiple concurrent employment arrangements under specific permit types, which is a meaningful change from where things stood a decade ago. Anyone weighing this up should read a proper explanation of can I work for two companies at the same time in the UAE before making assumptions based on how it works back home, because the permit layer genuinely changes the analysis.
The four things that actually matter in your case
Strip out the noise and it comes down to this.
Jurisdiction. Not where the company is headquartered. Where you work, and what the contract’s governing law clause says. These are sometimes different and the difference can be decisive.
Overlap. Same sector, same clients, same skills applied to a competing product? You’re in trouble regardless of drafting. Genuinely unrelated? Your position is far stronger.
Resources. Using the company laptop, the company subscription, or company time is the fastest way to lose an argument you would otherwise win. Keep the two lives physically separate. Different device, different email, different hours, no exceptions.
Disclosure. This is the one people get wrong. Most contracts require consent rather than banning outright, and most employers grant it when asked. Doing it quietly converts a permissible activity into a dismissible one, because now the issue is dishonesty rather than the second job itself. I’ve watched that turn a non-issue into a termination more than once.
What a sensible clause looks like
If you’re on the employer side of this, the blanket ban is the worst option available. It’s likely unenforceable in part, it signals distrust to every new hire who reads it, and it produces the exact behavior you don’t want, which is people not telling you.
The better structure is narrow and specific. Prohibit work for named competitors or defined competing activities. Require disclosure of other paid work, with consent not to be unreasonably withheld. Reference working-time limits where they genuinely apply. Keep confidentiality and IP obligations in separate clauses so they survive independently if the exclusivity provision gets struck.
That version is enforceable, defensible, and considerably more likely to be complied with.
Final thoughts
Can your employer contractually ban moonlighting? In principle, sometimes. In practice, far less often than the contract implies, and almost never as broadly as it’s written.
The clause in that highlighted contract was probably unenforceable in its full breadth. But my advice wasn’t to ignore it. It was to write a short email asking for consent, describing the freelance work accurately and confirming it uses no company resources and creates no conflict.
They sent it. Consent came back in two days, and the whole question stopped existing. Enforceability arguments are for after the relationship has broken down. Before that, a direct conversation resolves most of these, and it costs nothing but a small amount of nerve.
