Sibling Rivalry in Adulthood: How to Heal Old Wounds

You’re forty-three years old, sitting around the Thanksgiving table, and suddenly you feel like you’re eight again. Your brother makes that same dismissive comment about your career choices. Your sister rolls her eyes at something you said. The old familiar knot forms in your stomach, and you wonder why family gatherings still feel like a battlefield.

Here’s the thing nobody talks about: sibling rivalry doesn’t magically disappear when you blow out your eighteenth birthday candles. For many of us, those childhood dynamics follow us well into our adult years, creating tension that can last decades. But here’s what I’ve learned after years of watching families navigate these choppy waters—it doesn’t have to stay this way.

The Roots Run Deeper Than You Think

Most adult sibling rivalry has its roots in childhood experiences that never got properly addressed. Maybe you were the “responsible one” while your brother got to be the “fun one.” Perhaps your sister was labeled “the smart one” while you were stuck being “the athletic one.” These early family roles can become psychological prisons that keep us trapped in patterns we’ve long outgrown.

Dr. Megan Gilligan from Iowa State University has spent years studying this sibling rivalry phenomenon, and her research reveals something striking: even people in their 50s and 60s still carry feelings about perceived parental favoritism from childhood. That sting of feeling less loved or less valued can echo through decades of family interactions.

Why Smart, Successful Adults Still Fight Like Kids

The answer to sibling rivalry lies in something psychologists call “family systems.” When we’re around our siblings, we unconsciously slip back into the roles we played as children. It’s like muscle memory, but for emotions. That successful lawyer becomes the tattletale middle child. The accomplished doctor transforms back into the rebellious youngest. These patterns are so ingrained that they can override our adult reasoning and self-control.

Research shows that 85% of American adults have at least one sibling, making these relationships some of the longest we’ll ever have. Yet unlike friendships, which we choose and can end, sibling relationships come with a complex web of obligation, history, and family expectations that make them harder to navigate.

How Childhood Sibling Rivalry Shapes Your Adult World

The effects of unresolved sibling rivalry don’t stay contained within family walls. These patterns often spill over into our romantic relationships, friendships, and even our professional lives. If you grew up competing for your parents’ attention, you might find yourself competing with colleagues for your boss’s approval. If you learned to navigate conflict through passive-aggressive tactics with your siblings, you might use the same strategies with your spouse.

One woman I know realized she was recreating her childhood dynamic with her older sister in her marriage. Growing up, she’d learned that being “the good one” earned love and attention, so she’d become a people-pleaser who struggled to express her own needs. It took years of therapy to recognize this pattern and learn healthier ways of communicating.

When Family Gatherings Feel Like War Zones

Holiday dinners shouldn’t require emotional armor, but for many adults dealing with sibling rivalry, that’s exactly what they feel like. The competitive undercurrents, the old grudges that surface in seemingly innocent conversations, the way certain topics become landmines—it all points to unfinished business from childhood.

Clinical psychologist Eileen Kennedy-Moore puts it perfectly: “It’s hard living with people. They take your toys. They don’t do what you want.” As children, we don’t have the emotional tools to process these conflicts in healthy ways. As adults, we have a choice: we can keep replaying the same old scripts, or we can write new ones.

Breaking Free: Your Roadmap to Healing

The path forward isn’t about pretending the past didn’t happen or forcing artificial closeness. It’s about understanding your patterns and making conscious choices about how you want to engage. Here are the strategies that actually work:

Start with honest self-reflection. What role did you play in your family system? Were you the peacekeeper, the rebel, the achiever, the victim? Understanding your patterns is the first step to changing them.

Practice seeing your siblings as who they are now, not who they were at age ten. That brother who used to pull your hair might now be a devoted father. Your know-it-all sister might have learned empathy through her own struggles. People change, but we often keep relating to outdated versions of each other.

Set boundaries that protect your well-being. This isn’t about cutting people off—it’s about creating space for healthier interactions. Maybe that means limiting certain topics of conversation or setting time limits on visits.

Focus on what you can control: your own behavior. You can’t force your siblings to change, but you can choose how you respond to their behavior. When your sister makes that passive-aggressive comment, you can choose not to take the bait.

The Ripple Effects of Healing

When you break free from childhood sibling rivalry patterns, something beautiful happens: you don’t just improve your relationship with your siblings, you improve your relationship with everyone. Those communication skills you develop, that emotional intelligence you build, that confidence you gain—it all transfers to other areas of your life.

Studies show that adults with positive sibling relationships cope better with major life stressors like job loss, divorce, and health problems. Having a brother or sister in your corner can be one of life’s greatest gifts, but only if you can move beyond the old rivalries that keep you stuck in childhood patterns.

It’s Never Too Late to Start Over

Maybe you’re reading this and thinking it’s too late—too much water under the bridge, too many years of hurt feelings, too many patterns set in stone. But here’s what I want you to know: it only takes one person to change a family system. When you show up differently, when you refuse to play the old games, when you extend grace instead of grabbing for the old weapons, you create space for something new to emerge.

Your siblings might not change immediately. They might not change at all. But you’ll be free from the exhausting cycle of repeating the same conflicts over and over. And who knows? Your courage to break the pattern might inspire them to do the same.

Sibling rivalry doesn’t have to define your family story. You have the power to write a different ending, one conversation, one choice, one family gathering at a time. It starts with you, and it starts now.