A business alongside your job: what may your employer forbid?
Written by Ilias Aarrass6 min read · Published on · Last reviewed on 
In short
Since 1 August 2022 an employer may only ban side activities with an objective justification, such as working time law, health and safety, protecting confidential business information or a conflict of interest.
- Without an objective reason a side-activities clause is unenforceable; that reason need not be stated in advance, but must be available when invoked.
- A non-compete and a non-solicitation clause are properly enforceable and often affect your own business more than the side-activities clause.
- Your employed hours and your entrepreneurial hours count together towards the maximum working time under working time law.
- Your Chamber of Commerce registration is public, so arrange written permission before you register.
Starting alongside your job is the safest way in. The first question almost everyone asks is not a tax question but an employment one: am I allowed to do this? Since August 2022 the answer for most people is yes, even if your contract contains a ban. This article covers that side. The tax story, with the hours criterion and your two incomes stacking, is in part-time freelancing alongside a job.
The side-activities clause has been limited since 2022
Employers used to be able to ban side activities without giving reasons. That is no longer possible. Under the Transparent and Predictable Employment Conditions Act, a ban on side activities is only valid if the employer has an objective justification for it.
Valid grounds include working time law, health and safety, protecting confidential business information, or avoiding a conflict of interest. Simply wanting your attention on one employer is not a valid ground.
That reason does not have to appear in your contract in advance, but your employer must be able to give it at the moment they invoke the clause. If they cannot, the clause is not enforceable.
Three clauses to actually read
Besides the side-activities clause, most contracts hold two more provisions that can affect your business. Those two are, in fact, properly enforceable.
| Clause | What it covers | How strict |
|---|---|---|
| Side activities | Whether you may work alongside your job | Only valid with an objective reason |
| Non-compete | For whom and where you may work | Usually covers your own business too |
| Non-solicitation | Approaching your employer's clients | Strict, also after you leave |
How to have the conversation
Say what you are going to do and for whom, not how much you earn from it. Explain that it falls outside your working hours, that it does not compete and that you use none of your employer's equipment or client data. That addresses exactly the three concerns an employer is entitled to have.
Watch working time law too. Your hours with your employer and your hours as an entrepreneur count together towards the maximum working time. That is one of the few grounds on which an employer can genuinely make a ban stick, certainly with night shifts or safety-critical work.
Example: a designer employed at an agency
- Job
- 36 hours at a design agency
- Own work
- Websites for local business owners
- Non-compete
- Yes, aimed at the same market
- Outcome
- Permission for clients outside the agency's target group
Result: By agreeing in advance which type of client you will and will not take on, the employer gives written approval. You record that boundary so there is nothing to argue about later.
What to arrange before you register
Your Chamber of Commerce registration is public. So assume your employer can see it, even if you say nothing. Arrange permission first and only then handle your Chamber of Commerce registration.
Also check your collective agreement. Some collective agreements contain their own rules on side activities that go further than your individual contract, especially in healthcare, education and the public sector.
Frequently asked questions
Do I have to tell my employer I am starting a business?
If your contract has a side-activities clause, report it. Even without one it is wise, because your Chamber registration is public.
May I work for the same clients as my employer?
Almost never. That touches the non-solicitation or non-compete clause and is the fastest route to a dispute. Pick a different client segment.
May my employer dismiss me for starting a business?
Not just like that. Only if you breach a valid clause or cause demonstrable harm. Without an objective justification a ban does not hold up.
Does this apply to a temporary contract too?
Yes, the rule applies to every employment contract. In practice, though, an employer on a temporary contract is quicker to simply not renew it.
Sources
- A ban on side activities only with a good reasonKVK · kvk.nl
- Entering into an employment contractOverheid.nl · ondernemersplein.overheid.nl
Sources checked on
This article provides general information based on the rules known for 2026 and does not replace personal tax advice. For your specific situation, we're happy to take a look with you.
