What's the difference between a disciplinary and a grievance?

This sounds like a basic question. It isn't. The number of small business owners who start a disciplinary when they should be running a grievance, or ignore a grievance because they think it's a performance issue, is higher than anyone in HR likes to admit.

Getting the two confused doesn't just create procedural problems. It creates legal risk. And it usually makes the situation worse for everyone involved.

The simple version

A disciplinary is employer-led. It's the process you follow when an employee has done something wrong or isn't performing to the required standard. You're investigating, hearing the case, and deciding whether action is needed.

A grievance is employee-led. It's the process an employee uses to raise a concern, complaint, or problem at work. They're telling you something is wrong, and you need to investigate and respond.

One is "we have a problem with you." The other is "I have a problem with work." The procedures are different, the responsibilities are different, and the outcomes are different.

Why it matters

The ACAS Code of Practice on Disciplinary and Grievance Procedures sets out what's expected of employers for both processes. Tribunals use it as a benchmark. If you unreasonably fail to follow the Code, any compensation award can be increased by up to 25%. If the employee unreasonably fails to follow it, it can be decreased by the same.

Using the wrong process isn't just a technicality. It fundamentally undermines the fairness of whatever you're doing. If you run a disciplinary when the employee has actually raised a concern that should be treated as a grievance, you've ignored their complaint and punished them instead. That's a fast track to a constructive dismissal or victimisation claim.

When a disciplinary becomes a grievance

This happens more often than you'd think. You start a disciplinary process for poor performance. The employee responds by raising a grievance, claiming they've been bullied by their manager, or that they weren't given adequate training, or that the targets are unreasonable.

Now you've got two live processes that are connected. The question is what to deal with first.

The general guidance is that if the grievance is about the disciplinary process itself, or about the person conducting it, the grievance should be heard before the disciplinary continues. If the grievance is about something separate, both processes can run in parallel, but you need to be careful that one doesn't contaminate the other.

In practice, this is where things get complicated and where external support makes the biggest difference. Navigating overlapping processes requires someone who understands both procedures, can maintain independence, and can advise on sequencing without creating procedural unfairness.

When a grievance becomes a disciplinary

Sometimes an employee raises a grievance and the investigation reveals that the employee's own conduct is part of the problem. Maybe the grievance is about a breakdown in a working relationship, and the investigation shows that both parties contributed to it. Or the employee's grievance includes allegations that turn out to be false, and you need to consider whether that's a conduct issue.

Tread carefully here. An employee has a right to raise a grievance without fear of reprisal. If you respond to a grievance by launching a disciplinary against the person who raised it, you need to be very confident that the disciplinary is genuinely warranted and not retaliatory. Victimisation, treating someone unfavourably because they've raised a complaint, is unlawful.

The practical takeaways

Keep the two processes separate. Different procedures, different paperwork, different decision-makers where possible.

If an employee raises a concern during a disciplinary, take it seriously. Don't dismiss it as a tactical move even if you suspect it is. Document it, assess whether it's a formal grievance, and handle it properly.

Follow the ACAS Code for both. It's not optional. It's the minimum standard a tribunal will expect.

If both processes are running simultaneously and you're not confident about the sequencing, get advice. The cost of a conversation is trivial compared to the cost of procedural unfairness.

And if you're a business owner reading this because you've got a live situation that involves both a disciplinary and a grievance and you're not sure which way is up, you're not alone. It's one of the most common reasons people get in touch.

Book a free discovery call with King HR Advisory.