How to Write a Formal Complaint Letter About a Coworker

Table of Contents

1. Understand the Purpose of a Complaint Letter About a Coworker

A formal complaint letter about a coworker is used to report inappropriate behavior, unprofessional conduct, or workplace conflicts that affect productivity and the work environment. Common reasons for filing a complaint include:

Harassment or discrimination
Bullying or aggressive behavior
Unprofessional or unethical conduct
Failure to follow company policies
Disruptive or toxic behavior affecting teamwork

A well-structured complaint letter ensures your concerns are documented and increases the likelihood of an appropriate response from HR or management.

2. Identify the Correct Recipient

Before writing, determine who should receive your complaint:

Your Supervisor or Manager – If the issue affects work performance or team dynamics.
Human Resources (HR) Department – If it involves serious misconduct, harassment, or legal concerns.
Company’s Ethics or Compliance Office – For violations of company policies or ethical guidelines.

Check your company’s policies on reporting workplace complaints.

3. Gather Important Information Before Writing

Before drafting your letter, collect key details:

Coworker’s full name and job title.
Date, time, and location of the incident(s).
Names of witnesses (if applicable).
Description of the issue and its impact.
Previous attempts to resolve the matter (emails, meetings, verbal warnings).
Supporting evidence (emails, messages, security footage, HR reports).

4. Maintain a Professional and Objective Tone

Even if you are frustrated, your letter should be factual and professional. Avoid personal attacks, emotional language, or exaggeration, as a neutral complaint is more likely to be taken seriously.

🚫 Instead of: “My coworker is a nightmare to work with and makes my job miserable!”
✅ Say: “I have had repeated difficulties working with [Coworker’s Name] due to [describe specific behavior].”

🚫 Avoid ultimatums:
❌ “If you don’t fire them, I will quit!”
✅ Instead, say: “I hope to resolve this issue through appropriate action by management.”

5. Structure of Your Complaint Letter About a Coworker

1. Your Contact Information

Your full name and job title.
Company name and department.
Your email and phone number.

2. Date

Include the date you are writing the letter.

3. Recipient’s Contact Information

HR Manager’s or Supervisor’s name.
Company’s HR Department or office address.

4. Subject Line

Clearly state: “Formal Complaint About [Coworker’s Name].”

5. Opening Paragraph

Briefly introduce your complaint and the reason for writing.
Example:
“I am writing to formally raise a concern regarding the behavior of my coworker, [Coworker’s Name], in the [Department Name]. This issue has been ongoing and is affecting my ability to work effectively.”

6. Describe the Issue in Detail

What happened?
When and where did it occur?
Who was involved?
How has the issue affected you or the workplace?

Example:
“On [Date], during a team meeting, [Coworker’s Name] made inappropriate remarks about my work, which were dismissive and unprofessional. This was not an isolated incident, as similar behavior has occurred multiple times, creating a tense work environment.”

7. Attach Supporting Evidence

Include relevant documents such as:
- Emails or messages showing inappropriate behavior.
- Witness statements from colleagues.
- Reports from previous complaints or HR meetings.

8. Specify Your Desired Resolution

Clearly state what action you expect from HR or management.
Example:
“I kindly request a formal meeting with HR and my supervisor to discuss this matter. I also ask that [Coworker’s Name] receive a warning or appropriate training to address workplace behavior.”

9. Request a Response and Set a Deadline

Ask for a reply within a reasonable timeframe (e.g., 7-14 days).
Example:
“I would appreciate a response within 10 business days outlining the steps being taken to address this matter.”

10. Close the Letter Professionally

Thank HR or management for their time and cooperation.
Example:
“Thank you for your attention to this matter. I look forward to your response and a resolution that improves the work environment.”

11. Signature

Sign your name (if sending a physical letter).

6. Sample Formal Complaint Letter About a Coworker

[Your Name]
[Your Job Title]
[Company Name]
[Company Address]
[Email Address]
[Phone Number]
[Date]

Human Resources Manager
[Company Name]
[HR Department Address]
[City, ZIP Code]

Subject: Formal Complaint About [Coworker’s Name]

Dear [HR Manager’s Name],

I am writing to formally raise a concern regarding the behavior of my coworker, [Coworker’s Name], in the [Department Name]. This issue has been ongoing and is affecting my ability to work effectively.

On [Date], during a team meeting, [Coworker’s Name] made inappropriate remarks about my work, which were dismissive and unprofessional. This behavior has occurred on multiple occasions, creating a tense and uncomfortable work environment. I have attempted to address this directly, but the issue persists.

I have attached relevant documentation, including emails and statements from colleagues who have witnessed these interactions. Given the impact on my work, I kindly request a formal meeting with HR and my supervisor to discuss possible resolutions.

I would appreciate a response within 10 business days outlining the next steps. Please feel free to contact me at [Your Email/Phone] for further discussion.

Thank you for your attention to this matter. I look forward to your response.

Sincerely,
[Your Name]

7. Frequently Asked Questions (FAQs)

1. Can I file a complaint against a coworker anonymously?

Some companies allow anonymous complaints, but identifying yourself increases the likelihood of a proper resolution.

2. What if HR ignores my complaint?

If ignored, escalate the complaint to upper management, the ethics committee, or legal authorities if necessary.

3. How long should I wait for a response?

Most companies respond within 7-14 business days. If there’s no reply, send a follow-up request.

4. Can I take legal action against a coworker for workplace harassment?

Yes, if the behavior involves harassment, discrimination, or threats, you may seek legal advice or file a complaint with a government labor agency.

5. Should I try resolving the issue with my coworker before filing a complaint?

If possible, attempt to resolve the issue informally. If the behavior persists or is serious, escalate the matter to HR.

8. Conclusion

Writing a formal complaint letter about a coworker is an effective way to address harassment, unprofessional behavior, or workplace disputes. By keeping your letter clear, professional, and evidence-based, you increase the chances of a fair resolution. If HR does not respond appropriately, consider escalating the issue to upper management or legal authorities.

Martin taggart