A single toxic coworker can affect an entire team’s morale, trust, communication, and psychological safety, and left unchecked, that behavior can spread, normalize unhealthy dynamics, and contribute to a toxic culture.
When people hear me speak about toxic leadership or read my book, I Wish I’d Quit Sooner, one of the most common questions I receive is: “What if it’s not my boss? What if it’s my coworker?”
It’s an important question, because workplace toxicity doesn’t only come from people in leadership positions. A single toxic coworker can affect an entire team’s morale, trust, communication, and psychological safety, and left unchecked, that behavior can spread, normalize unhealthy dynamics, and eventually become part of the culture itself.
In other words, toxic workplaces aren't created by toxic bosses alone. Instead, toxicity can come from and spread from any level or role in an organization. It's defined by repeated harmful behaviors, that negatively impact other people’s well-being, engagement, and ability to do their best work.
I’ve heard countless stories of employees who manipulate coworkers, spread misinformation, divide teams, take credit for others’ work, undermine colleagues behind closed doors, or create constant drama that drains everyone around them. The position may be different, but the impact is remarkably similar.
Readers of I Wish I’d Quit Sooner will recognize the eight toxic boss personas. While I originally developed these to describe leaders, many of the same behavioral patterns also appear in coworkers. Some personas look slightly different when they aren’t coming from formal leadership roles. For example, a Control Freak coworker may not control your performance review, but they may attempt to control projects, meetings, communication, or decision-making in ways that create unnecessary stress and frustration.
A Gaslighter can still cause you to question your own reality, a Great Divider can fuel gossip and pit colleagues against one another, and a Dishonest Manipulator can shift blame and take credit for work that isn’t theirs. In the end, the outcome is often the same: people stop feeling safe.
Many people also underestimate how much influence one toxic employee can have on an entire team. Research consistently shows that toxic behavior spreads, trust declines, collaboration becomes harder, and psychological safety erodes.
It’s not unheard of to come across organizations where one toxic employee has created enough disruption that several high-performing people eventually resign.
If you’re working alongside a toxic coworker, start by recognizing that you cannot change another person’s behavior, but you can control how you respond. Document repeated patterns as well as isolated incidents, focus on observable facts rather than assumptions about intent, and set clear boundaries where possible.
If the behavior continues to affect your well-being or your ability to do your work, consider speaking with your leader or HR, and be specific about the patterns, their impact on you and the team, and how they’re affecting productivity or psychological safety.
Over the coming months, I’ll be exploring each of these toxic co-worker personas in greater depth: what they look like, why they behave the way they do, how they affect teams, and what you can do if you’re working alongside one.
I’m also excited to share that I am launching a Toxic Workplace Survivor Community this coming fall, bringing together people who are navigating these experiences and looking for support, education, and hope. If you or someone you know would like to learn more, or you'd like to be among the first to hear when it launches, please email connect@drlaura.live to join the waitlist, or sign up here.
Whether the toxicity comes from a boss or a coworker, one thing remains true: you deserve to work in an environment where you are treated with respect, where psychological safety endures, and where you can do your best work without constantly protecting yourself from someone else’s behavior.
Creating healthier workplaces starts with recognizing toxicity clearly, naming it confidently, and refusing to accept it as "just the way things are."
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Dr. Laura Hambley Lovett is an award winning Organizational Psychologist, Keynote Speaker, Business Leader, International Bestselling Author, and Podcast Host of the highly acclaimed podcast Where Work Meets Life™. She is a sought-after thought leader on workplace psychology, the future of work, and career development with over 25 years of experience. Dr. Laura is passionate about creating cultures that attract top talent and where people stay and thrive.
Dr. Laura has founded several psychology and consulting practices, including Canada Career Counselling in 2009, where registered psychologists across the country have helped thousands of Canadians navigate their career and workplace challenges, while supporting organizations to develop thriving leaders and cultures. She holds a Ph.D. in Industrial/Organizational Psychology from the University of Calgary, where she is currently an Adjunct Professor actively conducting research on toxic leadership across North America.
Her new book about toxic bosses, I Wish I’d Quit Sooner: Practical Strategies for Navigating and Escaping a Toxic Boss, endorsed by Dr. Marshall Goldsmith, was released on January 13, 2026, and became a #1 Amazon bestseller in Workplace Process & Infrastructure, as well as an Amazon International Bestseller. Drawing from her research and decades of experience, the book offers insight, validation, and practical strategies for those navigating, escaping, and recovering from a toxic boss at any stage of one’s career.
She has published two psychological thrillers, Losing Cadence and Finding Sophie, which aim to captivate readers while raising awareness about mental health and domestic violence. These novels are currently being adapted into a television series and inspired her to co-found WITH HER, a movement to end violence against girls and women. In recognition of her impactful work, Dr. Laura received a Canadian Women of Inspiration Award as a Global Influencer in 2018.
