Do I Have to Tell My Boss I Have a Second Job? Your Rights

Let's get the main thing out of the way: there is no general law in Australia that requires you to tell your employer about a second job. You're a free person. You can work wherever you want in your own time.

But — and this is a big but — your employment contract might say otherwise. Heaps of contracts include clauses requiring you to:

• Get written approval before taking on outside work
• Disclose any secondary employment or business interests
• Not engage in work that creates a conflict of interest
• Devote your full-time attention to the employer during business hours

If your contract has one of these clauses and you breach it, your employer could argue it's a valid reason for disciplinary action — potentially even dismissal. So before you pick up that second gig, dig out your contract and read the relevant sections.

If there's no clause about outside work? You're in the clear from a contractual standpoint. But there are still a few other things to think about.

Even without a specific contract clause, there's an implied duty of good faith and fidelity in every employment relationship. That means you can't do things that directly undermine your employer's interests.

Where this gets real: if your second job is with a direct competitor, or you're using your employer's confidential information, client lists, or trade secrets for your side gig — that's a conflict of interest and potentially a breach of your implied duties.

Examples that would get you in strife:

• Working for a competitor and sharing pricing information
• Starting a side business that directly competes with your employer
• Using your employer's client database to solicit business for your own gig
• Working for a supplier or client where you have decision-making power in the relationship

In these situations, you should absolutely disclose. Not because of some abstract legal obligation, but because getting caught creates a much bigger problem. The Fair Work Commission has upheld dismissals where employees concealed competing work, even when the contract didn't explicitly require disclosure. The breach of the implied duty of fidelity was enough.

Here's something most people don't think about: the National Employment Standards set a maximum of 38 ordinary hours per week for a full-time employee, and your employer can request reasonable additional hours on top of that.

If you're working 38 hours at Job A and then doing 20 hours at Job B, and your performance at Job A starts slipping because you're knackered — your employer has a legitimate concern. They can't sack you just for being tired, but they can performance-manage you if you're not doing your job properly.

There are also workplace health and safety obligations to consider. Under the Work Health and Safety Act 2011, both you and your employer have duties around fatigue management. If you're operating machinery, driving, or doing safety-critical work, fatigue from a second job is a genuine risk — and your employer may have a reasonable basis for asking about outside work commitments.

Some awards also have minimum break requirements between shifts. If you're finishing a shift at Job B at midnight and starting at Job A at 6am, you might be breaching those requirements, which creates issues for both you and your employer.

Use our work hours tool to check where you stand with maximum hours under your award.

Running a side hustle on an ABN is a bit different from having a second job as an employee. If you're doing freelance, contracting, or sole trader work on the side, you're running a small business, not working for someone else.

The same conflict of interest rules apply — don't compete with your employer or use their resources. But there's an extra layer: if your side hustle turns into something substantial, you need to stay across the tax implications.

When you're earning income through an ABN:

• You're responsible for your own tax on that income — it doesn't get withheld like PAYG
• If your ABN turnover hits $75,000 per year, you need to register for GST
• You'll need to lodge a tax return that includes both your employment income and your ABN income
• You can claim deductions for legitimate business expenses against your ABN income
• You might need to pay quarterly PAYG instalments to the ATO once they see you've got extra income coming in

One thing to watch: some employers try to argue that any outside work on an ABN breaches your contract. Unless your contract specifically prohibits it, running a small side business that doesn't compete with your employer is generally fine. They don't own your spare time.

If you're working two jobs as an employee (not on an ABN), the tax side is straightforward but catches people out every year.

You can only claim the tax-free threshold from one employer. That means your second employer should be withholding tax at the "no tax-free threshold" rate, which is higher. If you claim the tax-free threshold from both employers, you'll almost certainly end up with a tax bill at the end of the financial year.

When you start your second job, fill out the Tax file number declaration and make sure you tick that you do not want to claim the tax-free threshold from this employer. Your primary employer (usually the one paying you the most) should be the one where you claim it.

The extra tax withheld from your second job isn't money you lose — it's just withheld at a higher rate to cover the combined tax on your total income. When you lodge your tax return, it all gets reconciled.

Use our tax calculator to work out your combined take-home pay across both jobs, so you're not caught out at tax time.

So you've told your employer about a second job (or they've found out), and they're not happy. Here's how to handle it.

If your contract doesn't restrict outside work: Politely but firmly point that out. You can say something like: "I've reviewed my contract and there's no restriction on outside employment. My second job doesn't create a conflict of interest and doesn't affect my performance here." Keep it factual and in writing.

If your contract does restrict it: You've got a few options. You can ask for an exception or waiver — especially if the second job is clearly unrelated to your primary employer's business. Many employers will grant this if you're upfront about it.

If they threaten to sack you: Unless there's a genuine conflict of interest, a clear contractual breach, or your performance has actually suffered, dismissing you for having a second job is likely to be found unfair by the Fair Work Commission — especially if the second job has no connection to your primary employment.

Remember: restraint of trade clauses in employment contracts have to be reasonable to be enforceable. A blanket ban on all outside work of any kind is often considered unreasonable at law. If your employer is trying to enforce one, it's worth getting legal advice.