Why Siblings Fight — And What Parents Should (and Shouldn’t) Do About It

If your kids seem to go from best friends to bitter enemies in seconds, you’re not alone. As psychologist Dr. Lisa Damour shared on The Ask Lisa Podcast, sibling rivalry is part of growing up—and it often has less to do with parenting mistakes than with development.

“Kids want to differentiate,” explains Dr. Damour. “If one kid’s good at something, another wants to be good at something else so they’re not in direct competition with each other.”

That drive for individuality—especially as kids move into the tween and teen years—can look like rejection. The older one may suddenly think their younger sibling is too babyish, while the younger one feels left out or compared. This is often a natural evolution in the rivalry between siblings as they seek their unique identities.

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Sibling Rivalry: Why Kids Push Each Other Away

Dr. Damour points to three big reasons sibling rivalry can intensify as kids grow:

1. Comparison. Even if you’re not comparing them out loud, kids pick up on it. “Please tell them to stop comparing me to my older brother or sister,” one student wrote anonymously during a school session Dr. Damour led.
2. Fairness. Kids are laser-focused on what’s “fair.” As Dr. Damour puts it: “In a lot of families, fair doesn’t mean equal. Different kids need different things at different times.”
   When one child needs extra attention—say, for a health issue or emotional challenge—the other can feel overlooked or guilty for resenting it.
3. Proximity. Living together 24/7 creates friction. Research shows siblings can bicker dozens of times an hour! As Dr. Damour jokes, sometimes kids “fun fight” just to entertain themselves, an aspect of how sibling rivalry manifests.

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When to Step In—and When to Step Back

One of the hardest parenting calls is knowing when to intervene. Dr. Damour’s advice? Don’t rush in every time.

“Sometimes the best thing is to say, ‘You all need to work that out.’ There’s value in asking kids to sort this out and not having the adult intervene all the time.”

Constantly playing referee can actually worsen sibling rivalry—kids start fighting for your attention rather than learning to resolve things themselves.

But if one child crosses a line or there’s a clear power imbalance (for example, a teen being harsh to a younger sibling), that’s the time to step in. Calmly, firmly.

“Hey, that was not fair,” Dr. Damour suggests saying. “That’s not like you. Take a break.”

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Why Forcing a “Sorry” Doesn’t Work

It’s tempting to demand an apology and move on—but Dr. Damour warns it’s rarely effective.

“If it’s extracted, it’s not real,” she says.

Instead, she recommends two steps:

1. Stop the behavior with a simple, clear command: “Knock it off.”
2. Circle back later—when everyone’s calm—and ask, “Do you understand why I stopped you?” or “What can you do to fix it?” This approach helps to address and reduce sibling rivalry in a meaningful way.

That pause gives space for real repair—and helps kids learn empathy instead of resentment.

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Keeping the Long View

Even siblings who fight constantly can grow up to be close. The key is staying out of the day-to-day drama while modeling fairness, calm, and connection. Understanding the dynamics of sibling rivalry can help facilitate this process.

“You can’t make kids be friends,” Dr. Damour says. “But you can lay the groundwork.”

So next time your kids are at each other’s throats, take a breath. A little healthy rivalry can teach problem-solving, empathy, and resilience—skills that will last long after the bickering fades.

More on TodaysMama.com

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