Relationships | Family

26 Signs of a Toxic Sibling (With Expert Insights)

By Erika Maniquiz
Updated on

Having brothers and sisters should mean having allies for life—people who back you up and cheer you on. But sometimes, it feels like you’re dealing with an enemy instead. If you’re feeling hurt, undermined, or controlled by a sibling, it might be time to look closer.

In the next few paragraphs, we’ll explore clear signs that your sibling’s behavior may be toxic. From stealing the spotlight to belittling your achievements, these signs can help you identify an unhealthy relationship.

Disclaimer: The information provided in this article is for educational and informational purposes only and is not intended as a substitute for professional advice. If you are dealing with a challenging sibling relationship and need support, we recommend consulting a qualified mental health professional.

They Are Abusive Verbally and Emotionally

Verbal and emotional abuse can be incredibly damaging, especially when it comes from a sibling. It often starts subtly, with put-downs disguised as jokes leaving you uneasy. Over time, these comments become more frequent, making you question your worth.

Toxic siblings may also use emotional manipulation to control you. They might guilt-trip you into doing things for them or giving in to their demands. They may play on your insecurities, using your deepest fears and vulnerabilities against you.

You don’t deserve to be treated this way. It’s essential to set boundaries, seek support from trusted friends or family members, and prioritize your own well-being. You have the right to feel safe, respected, and valued in all your relationships.

They Gaslight You and Deny Wrongdoings

Gaslighting is a manipulative tactic that toxic siblings often use to make you doubt your own memories. They might deny events you know happened or twist the truth to make you feel like you’re going crazy.

Here are some common examples of gaslighting:

  • “I never said that. You’re imagining things.”
  • “You’re being too sensitive. It was just a joke.”
  • “That never happened. You’re making it up.”

Over time, this constant denial and minimization can leave you feeling confused and unsure of yourself. You might start to question your own judgment and wonder if you’re the problem.

Trusting your gut and standing firm in your own reality is important. Keep a journal of events if you need to, and surround yourself with people who validate your experiences.

"They often say things like, 'you’re being too sensitive' or 'learn to take a joke,' this may be a blaring red flag that they are gaslighting your feelings. They refuse to take any responsibility, often even victimizing themselves."

— Emilia Moskal | Parenting Content Specialist, HiJunior

They Use Your Weaknesses Against You

Toxic siblings have a knack for turning your weaknesses against you. This could be anything from using a past mistake to discredit your current efforts to leveraging your insecurities to embarrass you in front of others.

Here’s what this might look like:

  • You’re nervous about public speaking; they might bring this up right before you’re about to make a toast at a family event, throwing you off balance.
  • Or maybe you’re self-conscious about singing, and they insist you perform at family gatherings just to see you squirm.

Knowing your vulnerabilities gives them the upper hand. It’s a strategy to keep you one step behind. Recognizing this pattern is important because understanding their tactics can help you to set boundaries and seek support.

"This person [sibling] knows your vulnerability, your biggest regrets, things you feel ashamed of, your fears, traumas, and everything else that might hurt you. And they use all of this information against you."

— Amelia Prinn | Relationship Expert and Editor in Chief, Her Way

They Manipulate Situations to Make You Look/Feel Bad

Toxic siblings are masters at manipulating situations to make you look or feel bad. They might bring up past mistakes or embarrassing moments in front of others or twist your words to make you seem unreasonable or overly sensitive.

Real-life example: You accidentally forget to invite your sibling to a casual get-together. Instead of reaching out to you directly, they might tell your parents that you did it on purpose. By the time you explained your side, the damage had already been done.

If your sibling consistently manipulates situations to make you look bad, it may be time to limit your interactions with them or seek support from a therapist or trusted friend.

They Attempt to Control You

They act like they always know what’s best for you and disregard your own wants or needs. It’s a way for them to keep you dependent on their approval and decision-making. Toxic sibling’s need for control manifests in different ways, such as:

  • Trying to dictate who you spend time with or date.
  • Criticizing your choices or beliefs in an attempt to sway you.
  • Pressuring you to make certain decisions or take specific actions.
  • Using guilt or emotional blackmail to get you to do what they want.

This type of control can be incredibly suffocating and can leave you feeling like you have no autonomy over your own life. It’s important to remember that you are an adult and have the right to make your own choices, even if your sibling disagrees with them.

"If your sibling is always trying to control everything and everyone around them, that’s another sign that they might be toxic. They might do this by bossing you around or telling you what to do all the time."

— Mark Joseph | Founder, Parental Queries

They Sabotage Your Success

Have you ever had a big moment in your life, like a graduation or a job promotion, only to have your sibling find a way to ruin it? Maybe they made a scene at your celebration or downplayed your accomplishments to others.

Toxic siblings may feel threatened by your success, especially if they feel like they’re not measuring up in their own lives. They might try to undermine your achievements or make you doubt yourself, saying things like, “You just got lucky” or “Anyone could have done that.”

Your sibling’s jealousy or insecurity does not reflect your worth or abilities. It’s important to surround yourself with supportive people who celebrate your achievements and encourage you to keep growing.

They Blame You for Their Problems or Unhappiness

Do you notice how your sibling can never seem to take responsibility for their own issues? Instead, they find a way to blame you. You’re always the scapegoat for anything that goes wrong in their life.

What this actually looks like: When you are at a family gathering, and something goes wrong—maybe the food arrives late, a toxic sibling might blame you for not checking in with the caterers, even if it was their responsibility to shift the blame to you.

You are not responsible for your sibling’s happiness or success. You are not the cause of their problems, and you cannot fix them. Remind yourself that you are only in control of your own life and choices. Standing up for yourself is important to break this cycle.

They Use Guilt or Shame to Control You

Using guilt or shame as tools of control is a common strategy among toxic siblings. They often manipulate emotions to influence your actions, making you feel obligated to comply with their wishes and making you feel bad if you don’t do what they want.

Examples of using guilt or shame:

  • They might remind you of past favors they’ve done to compel you to help them in ways you’re uncomfortable with.
  • Suggesting that you’re a bad sibling for not supporting them in a disagreement, regardless of the context.

Your sibling’s attempts to control you through guilt or shame are not love or concern but power and manipulation. It’s okay to set boundaries and prioritize your own needs, even if it means disappointing your sibling. You are not responsible for their emotions or expectations.

"... if your sibling is always trying to make you feel guilty about things, that’s a sign that they’re not healthy for you to be around. For example, they might make you feel guilty for spending time with your friends or doing something they disapprove of."

— Mark Joseph | Founder, Parental Queries

They Constantly Criticize or Belittle You

Criticism can be particularly damaging as it often targets your self-esteem and personal identity. Whether it’s about your job, your lifestyle, or your choices, a toxic sibling finds ways to criticize, often under the guise of ‘just trying to help’ or ‘being honest.’

Ways they might criticize you:

  • Instead of congratulating you for a promotion, your sibling picks apart the company, the role, or even the salary, deflating your excitement.
  • Throw sarcastic remarks about your past failures or current choices that everyone else hears.
  • Publicly pointing out mistakes or flaws to undermine or humiliate you.

Continuously facing criticism can be draining and harmful to your self-esteem and mental well-being. Recognizing their patterns can allow you to confront the behavior or seek supportive relationships that affirm and encourage you.

They Play “Happy Family”

Toxic siblings often put on a façade of perfect family, particularly in public settings or when the attention of parents or other relatives is on them. This act can be confusing and isolating if you’re on the receiving end of their private hostility.

What this looks like: In a family gathering, they may laugh, joke, and appear incredibly supportive around you, but the dynamic shifts once the audience is gone.

This kind of behavior is super confusing and, honestly, quite draining. It forces you to play along with a charade. As I mentioned earlier, with emotional manipulation, this is just a public version of those same old tactics.

But their true colors will always show eventually. Trust your instincts, and don’t let their actions fool you. If you need support, reach out to a trusted friend, family member, or therapist who can validate your experiences and help you set boundaries.

They Lie or Break Promises Repeatedly

Honesty and trust are the foundations of any healthy relationship, but toxic siblings often have a hard time with both. They might lie to you about big things or small things, from where they were last night to whether they borrowed your favorite shirt without asking.

Lying and breaking promises is a way for toxic siblings to maintain control and avoid accountability. They might lie to get out of trouble or make promises they do not intend to keep just to make themselves look good.

If this is happening in your relationship, it’s important to call out the behavior and set clear boundaries around honesty and follow-through. You deserve to have a sibling who respects you enough to tell you the truth and keep their word.

They Actively Undermine Your Relationships

Toxic siblings often see your other relationships as a threat to their control over you. They might try to undermine your friendships, romantic partnerships, or even your relationships with other family members by:

  • Spreading rumors or lies about you to your loved ones.
  • Acting jealous or possessive when you spend time with others.
  • Telling you negative things about your friends or partner to make you doubt them.
  • Trying to monopolize your time and attention so you have less energy for other relationships.

If they’re actively trying to meddle in your other relationships, surround yourself with people who support you and want to see you happy, and don’t be afraid to distance yourself from anyone who tries to sabotage that.

"Your toxic sibling’s favorite activity is talking trash about you to everyone else—especially to your parents and other family members. They disclose your secrets and betray your trust whenever they have a chance. Of course, they make sure to twist the truth while they’re doing it."

— Amelia Prinn | Relationship Expert and Editor in Chief, Her Way

They Betray Your Confidence

Trust is important in any relationship, and when siblings share secrets, it’s based on a mutual understanding of privacy and respect. But a toxic sibling might betray this trust by sharing your secrets or using sensitive information against you.

Examples of betrayal:

  • Using your past mistakes as leverage in arguments.
  • Sharing your personal stories with others without your consent.

If you’ve been burned by a sibling who can’t keep a secret, it’s important to be cautious about what you share with them in the future. And if you’re really struggling to trust them, it might be time to find other sources of support.

They Are Narcissistic

Ever get that vibe from your sibling like the world revolves around them? Their needs, wants, and selfies should always take center stage? Unfortunately, it’s a trait that’s too common in toxic sibling relationships.

Narcissistic siblings can be incredibly draining and toxic to be around. They might:

  • Believe they are superior to you and others.
  • Exploit or take advantage of you for their own gain.
  • Have a lack of empathy for your feelings or experiences.
  • Constantly seeking attention and validation from others.
  • React with rage or contempt when they don’t get their way.

If you suspect your sibling might be a narcissist, educate yourself on the signs and patterns of this personality disorder. You can also seek support from a therapist who specializes in toxic family dynamics, as they can help you develop coping strategies.

"One of the easiest ways to tell if you have a toxic sibling is by determining if they are narcissistic. A narcissist will portray many toxic characteristics, including, but not limited to, blaming others, not showing remorse, and being manipulative."

— AJ Silberman-Moffitt | Senior Editor, Tandem

They Dismiss or Invalidate Your Feelings

Dismissing or invalidating someone’s feelings is a form of emotional abuse. It’s a way of telling someone their experiences and emotions don’t matter—that they’re wrong for feeling the way they do.

Over time, this kind of invalidation can lead to self-doubt, anxiety, and even depression. Your feelings are valid, no matter what your sibling says. You have the right to feel however you feel and to express those feelings in a healthy way.

If your sibling consistently dismisses or invalidates your emotions, it might be time to set some boundaries around communication. And if they continue to dismiss you, it might be time to limit your contact with them.

They Twist Situations to Make Themselves Look Better

In a toxic sibling relationship, it’s quite common to see one party constantly twisting facts to make themselves appear in a better light, often at your expense. This can be particularly frustrating and confusing.

How this manifests:

  • Rewriting the truth during arguments to make themselves the victim.
  • Altering stories when recounting them to others to gain sympathy or support.
  • They might exaggerate their own achievements or contributions while minimizing yours.

This behavior damages your reputation and can lead to you doubting your version of events. Trusting and being firm in your own truth is important. You don’t have to let your siblings control your reality or your relationships with others.

"A toxic sibling will want to appear as the 'better' sibling in front of others rather than be on your side. They are against you as if they were competing against you."

— Emilia Moskal | Parenting Content Specialist, HiJunior

They Invade Your Privacy and Violate Boundaries

Toxic siblings often have a hard time respecting personal boundaries. These invasions of privacy can feel like a major violation of trust. They might:

  • Barge into your room without knocking.
  • Snoop through your phone, email, or social media accounts.
  • Share your personal information or secrets with others without your consent.
  • Demand to know every detail of your life, even when you’re not comfortable sharing.

This kind of boundary-crossing is not normal or healthy in any relationship, even with a sibling. Speaking up and asserting yourself is important. You might need to put physical or digital barriers in place, like locks on your doors or password protection on your devices.

"This sibling has trouble setting limits on behavior and actions. They might steal or borrow items without asking, which is considered normal. 

Other siblings’ personal belongings are fair game for this sibling and they don’t care about what happens to the items after they've been taken and used."

— Colleen Wenner-Foy​, MA. LCMHC-S, LPC, MCAP​ | Licensed Clinical Mental Health Counselor | Founder and Clinical Director, New Heights Counseling and Consulting LLC

They Hold Grudges and Bring up Past Offenses

Do you ever feel like your sibling just can’t let things go? Like no matter how much time has passed or how many times you’ve apologized, they keep bringing up that one mistake you made years ago?

We all have moments we’re not proud of or things we wish we could take back. But in healthy relationships, people are able to forgive, learn from the past, and move forward.

If your sibling can’t seem to let go of your past, even after you’ve made amends and worked to change, it might be a sign that they’re more interested in holding power over you than in having a genuine, loving relationship.

They Rarely Apologize or Take Accountability

In healthy relationships, people are able to acknowledge when they’ve made a mistake or hurt someone else. This lack of accountability can be incredibly frustrating and hurtful. Toxic siblings might:

  • Blame you or others for their own actions or mistakes.
  • Make excuses or justifications for their hurtful behavior.
  • Refuse to admit when they’re wrong, even in the face of clear evidence.
  • Offer half-hearted or insincere apologies that don’t address the real issue.

Let them know that their lack of accountability is damaging and that they need to own their actions. If they continue to avoid responsibility, you might need to set firmer boundaries or distance yourself from the relationship to protect your own well-being.

"This [toxic] sibling never apologizes for anything they do wrong. Instead, they try to justify why they did something terrible."

— Colleen Wenner-Foy​, MA. LCMHC-S, LPC, MCAP​ | Licensed Clinical Mental Health Counselor | Founder and Clinical Director, New Heights Counseling and Consulting LLC

They Take Advantage of Your Kindness or Generosity

It’s wonderful to be generous, but not to the point where someone else starts to exploit it. A toxic sibling may see your kindness as an opportunity to benefit themselves, disregarding your well-being.

Examples of exploitation:

  • Borrowing money frequently without returning it.
  • Expecting you to always handle family responsibilities because “you’re better at it.”

Your kind gestures should not be taken as a sign to walk all over you. Knowing when and how to draw the line is important. Ensuring your generosity isn’t taken for granted is essential for maintaining respect and balance in the relationship.

"If you only hear from your siblings when they want something, then it’s a sure sign that they’re toxic. If any of your messages go unanswered but call with a request, it might be time to cut the cord."

— Bethany West McCarter | Teacher | Founder, The Travel Fam

They Insist on Playing the Victim

Toxic siblings love to play the victim card. No matter what happens or who’s really at fault, they always find a way to make themselves out to be the innocent party who’s been wronged by everyone else.

They might:

  • Blame others for their own mistakes or shortcomings.
  • Constantly complain about how unfair life is or how everyone is out to get them.
  • Use their “victim status” to guilt you into doing things for them or letting them off the hook for bad behavior.

If your sibling always paints themselves as the martyr or the mistreated party, it can be hard to have a genuine, balanced relationship with them. Recognizing this pattern can help you approach interactions carefully and prevent enabling their behavior.

They Get Excessively Jealous or Competitive with You

Toxic siblings often see your successes as a threat to their own ego and sense of self-worth. They might try to tear you down or minimize your achievements to make themselves feel better, or they might try to copy or outdo you in everything you do.

Common signs include:

  • Constantly comparing their achievements to yours.
  • Undermining your successes or attempting to outdo you at every opportunity.

It’s important to recognize that this competitiveness stems from their insecurities and possibly deeper issues. Addressing it directly or through family mediation can sometimes help ease the tension and reintroduce a healthier family dynamic.

"But in a toxic relationship, one sibling may always try to one-up the other. This competitive behavior can damage self-esteem and lead to jealousy and resentment."

— Sarah Watson | Psychologist | Certified Life & Career Coach | Chief Operating Officer, Best Personality Tests

They Start Arguments with You

Toxic siblings love to stir drama and conflict, even over the smallest things. They might pick fights with you over petty disagreements or bring up old grudges and resentments just to get a rise out of you.

They might also use arguments to control or manipulate you by making you feel guilty, defensive, or like you’re always in the wrong. Here are some common ways that toxic siblings might start arguments:

  • Nitpicking or criticizing your choices, opinions, or behavior.
  • Using sarcasm, insults, or personal attacks to get under your skin.
  • Twisting your words or taking things out of context to make you look bad.
  • Playing devil’s advocate or taking the opposite side of every issue just to be contrarian.

If you’re struggling with a sibling who loves to argue, you can let them know that you’re not interested in engaging in unnecessary drama, and you might need to limit your contact with them to protect your own peace of mind and well-being.

"If you find yourself constantly arguing with your sibling (and it’s not just the occasional disagreement), this is a sign that something is wrong. Healthy siblings are able to disagree without resorting to name-calling or personal attacks. 

If you find yourselves constantly fighting, it’s time to sit down and talk about what’s going on."

— Sarah Watson | Psychologist | Certified Life & Career Coach | Chief Operating Officer, Best Personality Tests

They Treat Others Badly

If your sibling is consistently rude, dismissive, or cruel to their friends, partners, or other family members, it’s a sign that they have some serious issues with empathy, respect, and kindness.

How a person treats others often reflects their true character and a toxic sibling who consistently behaves poorly towards others can bring negativity into your life.

You might worry about their impact or feel guilty by association. But you can’t control how they treat others. What you can do is model healthy, respectful behavior in your own relationships and set clear boundaries about what you will and won’t tolerate.

They Refuse to Compromise

Finding a middle ground where both people feel heard, respected, and valued, even if they don’t always get their way. But toxic siblings often have a hard time with compromise because they see it as a sign of weakness or a threat to their control.

Dealing with a sibling who refuses to compromise can be incredibly frustrating, but it’s important to remember that compromise is a two-way street. You have the right to assert your needs and boundaries and expect your sibling to respect them.

This might mean having some difficult conversations or setting firm limits on what you will and won’t do. But if your sibling consistently refuses to budge or consider your perspective, it might be a sign that the relationship is not as mutual or supportive.

"In a healthy sibling relationship, both parties are willing to compromise when necessary. If your sibling is always demanding things go their way, this is a sign of toxicity."

— Sarah Watson | Psychologist | Certified Life & Career Coach | Chief Operating Officer, Best Personality Tests

They Feel You Got More Attention Than They Did

Sibling rivalry might be a common issue, but for toxic siblings, it can become an obsession that consumes their thoughts and actions. They might feel like they got more love, attention, or resources from their parents growing up, and they hold onto that resentment.

How this often unfolds:

  • Expressing continuous resentment or jealousy towards your achievements.
  • Making passive-aggressive comments that imply favoritism whenever you succeed or gain recognition.
  • They fish for compliments or create situations where they become the center of attention, often at your expense.

This sense of jealousy might be traced back to childhood experiences. Initiating open discussions about perceived favoritism with family therapy could be beneficial in addressing this sense of unfairness and bitterness.

"If you have a toxic sibling, they may seek attention no matter how they receive it. Some toxic siblings thrive off of knowing that people are paying attention to them, even when they are sharing some form of drama."

— Dr. Jaclyn Gulotta,  LMHC | Licensed Mental Health Counselor, Choosing Therapy

More Insights from the Experts

“A toxic sibling will often put you down in an attempt to make themselves feel better. They may belittle your accomplishments or criticize your choices in an effort to make themselves look and feel better.”

— Sarah Watson | Psychologist | Certified Life & Career Coach | Chief Operating Officer, Best Personality Tests

“Toxic siblings can be ego-driven because they are self-absorbed and do not have time for others’ feelings. They may come across as defensive and have little to no gratitude.

When you are spending time with them, it feels like they only want to talk about themselves and have no desire to ask about you.”

— Dr. Jaclyn Gulotta, LMHC | Licensed Mental Health Counselor, Choosing Therapy

“This [toxic] sibling treats others with disrespect and cruelty. They’re usually highly competitive and jealous of other siblings and won’t hesitate to bully or hurt them just because they can.”

— Colleen Wenner-Foy​, MA. LCMHC-S, LPC, MCAP​ | Licensed Clinical Mental Health Counselor | Founder and Clinical Director, New Heights Counseling and Consulting LLC

“They [toxic siblings] do not take the time to listen to you. Everything is a competition for attention; they try to make you feel guilty, boundaries do not exist, and there is very little trust due to history.”

— Kimberly Schaffer, MSW, LCSW, CSSW, CCS | Practice Founder, Attentive Psychotherapy & Counseling Center

“The toxic sibling is not at peace with themselves or most other family members. They may feel deeply vulnerable, abandoned, or betrayed by family members or others. The thinking is that it doesn’t always matter who or what is responsible, but someone has to take the flak, and one’s siblings are a good target.”

— Hephzibah Kaplan | Director, London Art Therapy Centre | Author, “Almost Happy: Pushing Your Buttons with Reverse Psychology“

“We all have siblings who don’t care about us… If you feel like their comments and criticism are more harmful than helpful to build confidence in yourself, then something may be wrong with the relationship—toxic or not!”

— Mark Joseph | Founder, Parental Queries

“To move forward, it’s essential to set boundaries to protect yourself. This could mean cutting off contact or forging toxic relationships with them. It will not be easy. Therefore, it is vital to have a strong support network as well…”

— Pamela Li | Author | Editor in Chief | Founder, Parenting For Brain

Frequently Asked Questions

What should I do if I suspect my sibling is toxic?

First, assess the interactions and their impact on your well-being. Consider speaking to a mental health professional for guidance. If feasible, have an honest conversation with your sibling about your feelings and set clear boundaries.

Can toxic sibling behaviors change over time?

People can change if they are willing to work on their behaviors and if they recognize the impact of their actions. However, change is a personal decision and often requires professional intervention and a lot of effort.

What should I do if other family members don’t see the toxicity?

It’s common for family dynamics to mask toxic behaviors, making it hard for others to see what you experience. In such cases, maintain your stance and seek external support from friends or a therapist.

Over time, keep the communication factual and non-emotional when discussing issues with family members.

What if my toxic sibling refuses to acknowledge their behavior?

In such cases, it’s important to focus on your own feelings and reactions. You can’t force someone to see what they don’t want to, but you can protect yourself and seek support.

Final Thoughts

Identifying toxic traits in a sibling can be tough, especially when you care about them. But acknowledging these issues is important for healing and growth. You can choose to talk things out, set needed boundaries, or seek advice from someone who can help professionally if things are really challenging.

Your well-being matters. It’s okay to look after yourself by adjusting how you interact with your sibling. Take small steps towards change, and don’t rush. Healing takes time, but you’re not alone on this path.

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Erika Maniquiz

Erika Maniquiz is a certified teacher and librarian with a Library and Information Science degree. She cherishes the calm moments reading books as much as the dynamic discussions she has in her classroom. Beyond her career, she is a fan of Kdrama and loves Kpop's lively beats.