You’ve seen it happen before: One of your direct reports has suddenly (or maybe not so suddenly) become a nuisance. In meetings, they’re rejecting good ideas and putting down bad ones. Or they’re constantly complaining about their work or someone else or some company initiative. Or they never seem to see the positive in what you’re working on as a team.

“I like to call these people the ‘Naysayers,’” says Melody Wilding, a licensed social worker, professor of human behavior at Hunter College, and performance and career coach on The Muse. “That person who always pokes holes in everything, always kind of has a bad attitude, and points out why things are not going to work.”

Everyone’s crossed paths with a negative employee–someone who always seems to be in a bad mood, who’s not being productive, and who’s difficult to work with, whether because they say no to everything or because their pessimism brings down everyone around them.

This kind of attitude can be disruptive and destructive for any team dynamic, affecting how the person’s co-workers stay focused, motivated, and happy at work. Plus, it doesn’t exactly help with getting stuff done, either.

It can be incredibly infuriating to manage a negative employee’s behavior–and as their boss, you may have the urge to let it go and hope the person just quits, or the situation eventually gets better on its own. But trust me, it won’t.

So how can you handle this type of person calmly and professionally? Here’s what the experts have to say about dealing with negative employees.