The Vexatious Complainant: A Hard Truth of Workplace Investigations

If you’ve been investigating long enough, you’ve met them. The individual who knows the policy inside and out. Who understands just enough legal terminology to frame a complaint in a way that triggers the duty to act. Who files complaints—again and again. And who, when their allegations are examined, often leaves a pattern that raises a difficult but important question: Is this a legitimate concern or a misuse of the process?

This is the vexatious complainant.

It’s a tricky subject. No one wants to dismiss a complaint prematurely or discourage employees from coming forward. After all, many of the most serious and valid concerns often come from people who have already made multiple attempts to be heard.

But there are moments (rare but real) when the pattern becomes clear. And when that happens, it’s not just frustrating. It’s corrosive.

Why It’s Important to Spot Them

Spotting a vexatious complainant isn’t about casting doubt on legitimate concerns. It’s about ensuring that investigative resources are used responsibly and that the integrity of the process is preserved for everyone. Here are five reasons why identifying this behaviour matters:

1. It Erodes Trust in the Process

When other employees see someone weaponize the complaints process repeatedly, especially when the allegations (despite all the buzzwords they may contain) don’t hold up under scrutiny, they begin to lose faith. It sends a signal that the process is easily manipulated, and that genuine concerns might be treated with suspicion because of someone else's track record.

2. It Creates a Chilling Effect on Legitimate Complainants

Ironically, a vexatious pattern can deter real victims from coming forward. They fear being lumped into the same category or worry that their experiences won’t be taken seriously because someone else has “cried wolf” too many times.

3. It Causes Unnecessary Strain on the Workplace

These complaints often create ongoing tension between employees and management, or between coworkers, especially when the same individual has made complaints against multiple people. The emotional toll adds up. Not just for those accused, but also for colleagues who are pulled into investigations as witnesses or mediators.

4. It Results in Avoidable Costs

Investigations require time, money, and energy. Even when a complaint is ultimately unsubstantiated, the effort involved to explore it thoroughly is significant. For employers, particularly in resource-strapped environments, this becomes more than just a procedural issue: it becomes a financial one.

5. It Skews the Employer’s Understanding of Organizational Risk

If the same employee raises frequent complaints, their file can begin to dominate the narrative. This creates the illusion of widespread conflict or dysfunction where there may be none. It clouds the employer’s ability to see the real hotspots in the organization.

How to Handle It Professionally

Addressing the behaviour of a vexatious complainant is not easy. It must be done with precision, fairness, and a careful separation of the complaint from the complainant. Here are three principles to guide the process:

1. Stay Anchored in Process, Not Personality

The most dangerous response is to dismiss a complaint because of the person making it. That opens the door to bias, liability, and a potential chilling effect on others. Instead, assess each complaint on its own merit: follow the usual steps, apply the same scrutiny, and document everything. Over time, if a pattern emerges, you’ll have a factual basis to speak to it.

2. Consider a Pattern Review Post-Investigation

At the end of the investigative process, take a broader view: How many prior complaints have been made? Against whom? What were the findings? If it becomes clear that a complainant is consistently bringing forward unsubstantiated allegations with a similar tone or structure, it may be time for a pattern review. This can be done internally, or, where warranted, by a neutral third party.

3. Communicate Boundaries and Expectations Clearly

Employers can set limits. If a complaint is filed that repeats prior allegations or presents no new information, it’s fair to inform the employee that the matter has already been addressed. Policies on frivolous or vexatious complaints can help provide a roadmap, but these must be communicated clearly and applied carefully.

What Makes It So Difficult

Here’s the challenge: vexatious behaviour isn’t always clear from the outset.

Many complainants are upset, persistent, and deeply invested in the outcome. That doesn’t make them vexatious: it makes them human. In fact, one of the reasons vexatious complainants are so difficult to identify is because the process rightly protects and validates emotional expression.

Often, it's only when the full record of multiple complaints is reviewed that the pattern emerges. And even then, there may be nuances: some elements of the complaints may be legitimate, even if the broader conduct is concerning. The line is rarely bright.

That’s why investigators and employers must approach the matter with humility. An over-eager diagnosis of vexatiousness can be just as damaging as ignoring it altogether.

Which brings us to the most important skill in handling these situations: discernment.

And discernment, in investigations, doesn’t happen in isolation. It grows with experience, reflection, and (when available) peer review. Taking the time to vet findings with a trusted colleague or legal advisor can protect investigators from unconscious bias and ensure that any conclusions about a complainant’s conduct are fair and evidence-based.

Calling a Spade a Spade

No one enters the workplace hoping to become “that person.” Even those who exhibit vexatious behaviour often start from a place of genuine frustration, misunderstanding, or a history of being ignored.

But at a certain point, when the pattern is clear and the impact is real, the behaviour must be named. Not to shame the individual, but to protect the process.

What’s your take?

Have you encountered this challenge in your own work? How did you navigate it? Do you agree with the idea that vexatious complainants exist? Or do you think the term is too easily misapplied?

Let’s continue the conversation.