11 Tips On How To Deal With A Narcissistic Younger Sister

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Narcissistic siblings can often do as much damage as a narcissistic parent. They are selfish, controlling, manipulative, and constantly need attention. They can cause so much trouble that they can actually tear a family apart.

Younger narcissistic younger sisters are often spoiled by their parents, and they can develop narcissistic personality disorder as a result. Moreover, they become very entitled and treat their siblings as they would servants. So how can you deal with that from a narcissistic younger sister? 

Since a narcissistic younger sister won’t likely change her ways, you have to be strong in setting boundaries, avoid justifying yourself, don’t call out her narcissism, and stay away as much as you can. It also helps to get therapy for yourself. Another thing you must consider is going no contact. 

One thing different with a narcissistic sibling is that they sometimes know you even better than your parents do. This is particularly true with a narcissistic younger sister, who you may have always thought of as your adorable baby sister, except she’s not so adorable anymore.

That’s why you need to know how to deal with her, how she is different from other narcissists, and how she will undermine the family dynamic. 

How is a Narcissistic Younger Sister Different from Other Narcissists?

How is a Narcissistic Younger Sister Different from Other Narcissists

Narcissists all share common characteristics, and your narcissistic younger sister also has the following common traits: 

  • She seeks out attention
  • She feels entitled
  • She needs a constant supply of adoration
  • She is self-absorbed
  • She is quick to criticize
  • She erupts in explosive narcissistic rage
  • She doesn’t respect boundaries
  • She feels wronged by everyone around her
  • She won’t admit her responsibility for mistakes

What makes a narcissistic younger sister different, however, is that it’s very common for parents and other family members to enforce many of her bad behaviors. Baby sisters are often spoiled excessively, and sometimes, this is what causes their narcissism, as you can see in this video

When a narcissist consistently has their bad behavior validated, meaning it works for them, they not only continue to act that way but they also up the ante. They see they can manipulate people easily, and they start doing it more and more. 

As a consequence of the positive reinforcement they receive, a narcissistic younger sister sees that as validation that the grandiose ideas she has instilled in her false self-image are true. It encourages her to continue on just as she has been doing. 

Basically, it’s not that your narcissistic younger sister is that different than other narcissists, but it’s the level of encouragement she receives from family members who think of her as the baby of the family. That reinforces her grandiose ideas of superiority and power, and it results in more misery for the rest of the family. 

How Does a Narcissistic Younger Sister Undermine the Family Dynamic?

How Does a Narcissistic Younger Sister Undermine the Family Dynamic

A narcissistic younger sister can do significant damage to the family dynamic. Narcissists love to create drama by manipulating family members. 

It also makes them feel powerful when they think they can cause all those problems in a few simple steps. One of the main techniques they use to do this is triangulation. 

Your narcissistic younger sister, for example, might tell your brother something bad you said about him, and then she might tell you that he said something bad about you. If you don’t know she’s playing a game, you and your brother could harbor resentment against each other without either of you knowing why. 

In this way, your narcissistic younger sister can undermine the family dynamic and cause rifts that are baseless. She will also play this game with your parents, and if you don’t want someone to know something, you should never trust a narcissist with a secret. 

Many narcissists engage in emotional blackmail against their victims. They threaten to reveal secrets and tell other stories to manipulate you. Moreover, no matter what they say about keeping a secret, they will often reveal it anytime it benefits them, even if you did what they wanted! 

In short, narcissists lack any kind of family loyalty. They will stab you in the back while charming you to your face, and narcissistic younger sisters are particularly good at this because they’ve been the adored baby of the family for so long. 

How Can You Deal with Your Toxic Baby Sister?

How Can You Deal with Your Toxic Baby Sister

It can be very difficult, if not impossible, to deal with your narcissistic baby sister in a reasonable manner. The truth is that she doesn’t think in a logical manner. She is guided by one thing and one thing only – her need to get narcissistic supply so she can feel good about herself. 

That’s why it’s vital for dealing with your narcissistic sister to be extremely clear, and you might want to document things she says and does. You also need to practice self-care so that you can process the abuse you’re experiencing. 

Here are several tips for dealing with your narcissistic younger sister in an effective way. Most of these are effective tools for dealing with narcissists in general too. 

1. Broken Record Alert – Boundaries!!

I know that I am constantly harping on setting strong boundaries and enforcing them consistently, but it really is the only way to deal effectively with narcissism

Before giving you some helpful boundaries to set, it’s important that you understand what boundaries are really all about. We think of boundaries as ways we can force other people to do something like respect us or treat us fairly. 

Boundaries are really all about respecting yourself, however, and treating yourself fairly. They are not about making other people do anything. Your boundaries are your way of telling yourself that you will take good care of yourself! 

With that understanding, here are several boundaries you will want to set with a narcissistic younger sister. 

  • No yelling
  • No name calling
  • No lying
  • No gaslighting
  • No going behind my back
  • No projection
  • No tattle-telling

When you set whatever your boundaries are with your narcissistic sister, you also want to let her know what the consequences for any violations will be. You might even consider giving her these in writing so she can’t claim she didn’t know. 

The consequences can be anything from leaving the room to going no contact. What exactly they are is up to you and what you can tolerate. Consider it carefully, and be clear when you tell her where the line is located. 

2. No Justifications

No Justifications

When you do or say something to your narcissistic younger sister, don’t justify your actions, opinions, or statements to her. To understand how it will make her see you, you have to remember that her personality disorder makes her feel superior to everyone around her. 

If you try to justify or even explain your actions to her, she will interpret that as you being weak, and if you’re weak, she will exploit that fact. She has no empathy, so she can’t understand how her actions affect you. 

Even if she is able to intellectually understand the consequences of her actions, she has no emotional connection to them. She won’t have compassion for you in any circumstance, and anything you do to explain or justify your position will just inflame her more. 

Instead of justifying or explaining or arguing, just tell her what you’re going to do or what your opinion is, and move on. You might feel the need to explain more, but doing so will undermine any authority you have in her eyes. 

She won’t ever fully understand or agree with your side of an argument, so you’re only wasting your breath trying to justify your actions or opinions. 

3. Remember You Have Choices

When you have a narcissist in the family, it can feel like there aren’t any good options. It can be very frustrating to feel like you’re blocked at every turn. 

A narcissist will put up as many roadblocks as they can to force you into doing what they want you to do. That’s why it’s very important to remember that you have choices. You don’t have to just give in to what they want. 

“Letting go of toxic people in your life is a big step in loving yourself.”

Hussein Nishah, 16th Century Punjabi Muslim Sufi Poet

Even if you’re only good choice is walking away or cutting them out of your life, that’s a choice you can make. It might be the only real choice you have to avoid their constant abuse. 

When you find yourself feeling overwhelmed, take a step back and remember that you don’t have to continue to put up with your narcissistic younger sister’s abuse. You have at least one good choice that you can make to end the abuse. 

4. Reinforce Her Choices

Reinforce Her Choices

My friend’s narcissistic younger sister is always making herself out to be the victim of all the other family members. She rages on and on about how terribly other people treat her, especially her parents, who have supported her and enabled her bad behavior for years. 

When my friend can’t stand it anymore, she reminds her toxic sister that she has made choices that have put her in that situation, and she can make choices to get out of it, too. That often shuts down the toxic raging because her sister can’t deny she has those choices. 

Narcissists often present any situation they don’t like as if they’re a hapless victim of circumstance who can’t change anything. They want other people to pity them and act accordingly. 

The only way to deal with this kind of behavior is to put it right back onto your toxic baby sister. Point out the choices she has made that have contributed to her problems and the choices she could make to improve her situation. 

From there, you can free yourself of any responsibility to act. You’ve let her know your opinion of the choices she has made and the better ones she could make. That’s all you can reasonably do. 

5. Don’t Back Down

When you are confronted with your narcissistic sister’s rage and abuse, if you back down from her,  you’re giving her the power to continue acting that way. You have to stand up to her and not back down. 

It’s not backing down, however, to simply leave the room until everyone can calm down. If she is behaving in an unacceptable manner, simply say, “I don’t allow anyone, including you, to talk to me that way, so I’m leaving.” 

Leave without saying another word. This will likely make her worse at first, but when she sees that you mean business, she will eventually change her ways. She won’t be less narcissistic, but she will be less directly abusive to you.

6. Insist on Courtesy

Insist on Courtesy

At the first sign of toxic behavior, remind your narcissistic younger sister that she will have to be courteous when she is dealing with you. Tell her that you will walk away from the conversation and refuse to talk to her until she acts in a courteous manner. 

“When you notice someone does something toxic the first time, don’t wait for the second time before you address it.”

Shahida Arabi, Psychologist, Sociologist, and Bestselling Author

You can’t really let it go one time or your toxic sister will see that as weakness. She will continue to behave badly whenever she pleases because she won’t believe you will do anything about it. 

7. Stop the Conversation

If you’re in an argument with your narcissistic younger sister, you’re wasting your time. A narcissist will never admit they’ve done anything wrong, and they will always seek to blame other people

You’ll never convince her that she had a role in any dispute or that she should have behaved differently. Narcissists are too full of toxic shame to admit such a thing. If they did, they would face the possibility of a narcissistic collapse. 

Since you’re not going to get anywhere with her, it’s just better to stop the conversation and walk away. That can be very difficult sometimes because you want to try to convince her of your side of things. But it won’t work. 

The sooner you realize that your best option is to just stop talking and walk away, the better. It will also send a strong message about your boundaries to your little sister when you do so. 

8. Avoid Interactions

Avoid Interactions

If nothing else works, you can simply choose to avoid any interactions at all with your little sister. My friend started doing this because every time she talked to her little sister, her sister would make loaded statements that were veiled accusations. 

It was her sister’s way to to accuse her of things without really making the accusation directly. If my friend would respond, her sister would simply deny having meant anything like that, but it was clear she did. 

It’s a kind of passive-aggressive way that narcissists will try to get their point across without having to talk directly about whatever’s bothering them. It’s very toxic and frustrating for the people around them. It can be difficult to remain calm, but this video has some strategies that can help. 

Sometimes avoiding interactions with such a person is the only response you can have. If you have to be around them at a family gathering, for example, you can simply fill your time talking with someone else. 

“Sometimes it’s better to end something and try to start something new than imprison yourself in hoping for the impossible.”

Karen Salmansohn, Bestselling Author

If your toxic baby sister comes over to talk to you, excuse yourself to use the restroom or let her know that, unfortunately, you have to leave now since you have a date to meet someone else. 

It’s not cowardice to avoid these kinds of confrontations, it’s simply the only way to avoid the emotional abuse your narcissistic sister heaps on you and other family members. It’s actually the most logical thing you can do if you still must see her from time to time. 

9. Watch Out for Triangulation

Your narcissistic sister will employ triangulation to destroy your relationship with other family members. The best thing you can do to combat this is to keep the lines of communication open with family members, so you know when she’s said something. 

If you hear something about a family member, go to them directly and tell them what she said. If they really did do or say what she said, then you need to clear the air with them, but most likely, you’ll find out it was a lie

If you keep each other informed about what she says and does, you can prevent the kind of long-term relationship damage that often results from this kind of behavior. It’s the only way to prevent yourself and your family members from building up resentment for reasons you don’t even know about. 

10. Be Bluntly Honest at All Times

Be Bluntly Honest at All Times

It’s important to practice blunt honesty with your narcissistic younger sister at all times. You might not want to start a fight, and you are probably normally very courteous and kind, but if you try to be that way with your sister, she will take advantage of you. 

You have to simply tell the truth at all times. When she says something that hits you wrong or that you feel is unkind, say something to her right at that moment. Let her know that’s not okay and that you won’t permit it. 

If she can’t treat you with respect and kindness, you will break off all contact with her. Narcissists really don’t like that, so it will have an effect. As I’ve said before, she won’t be less narcissistic, but she will start to treat you differently to avoid the consequences you’ll impose if she crosses a line. 

11. Keep a Journal of What Happened

Finally, a good strategy to employ with dealing with a narcissistic younger sister is to keep a journal of things that happen and things she says. Narcissists are experts at gaslighting. They want to make you think that what you thought you heard or saw isn’t what actually happened. 

They want you to question your interpretation of reality. That way, you’ll have to rely on them to get the correct interpretation. Clearly, that’s not what you want, so keeping a journal can help you remember exactly what happened. 

If you have a conversation with her, and she says something, write it down when it’s still fresh in your memory. If it ever comes up again, you can go to your notes to remind yourself of exactly what happened. 

It’s also helpful to add in how you interpreted what she said or did at the time. Your narcissistic baby sister might try to tell you she was only joking or that you’re too sensitive, but how you felt about what she said at the time is a good indicator of what she really meant. 

You can go back over it with her and let her know that if she meant that as a joke, it wasn’t funny. This is a great tool to keep her from distorting your reality, and it gives you control over your own interpretation of reality. 

Final Thoughts

Narcissistic siblings can be as toxic as narcissistic parents, and they can do just as much damage to your self-esteem and the family dynamic. They wound you on an emotional level, and then they use those emotional triggers to try to manipulate and control you. What’s more, sometimes they know you better than even your parents know you. But there are ways you can control how much their toxicity affects you, even if the narcissist in question is your adorable baby sister. 

I’ve created a method that can help you identify your emotional triggers and defuse them. Once you’ve done that, you can heal the wounds that created them and free yourself from narcissistic manipulation and control. It’s called the 5-Step Roadmap to Heal Emotional Triggers, and it’s completely free. If you would like a copy of this handy guide, just click on the link here and I’ll send it directly to your inbox today! 


If you want more tips for dealing with narcissists, setting boundaries, and managing emotional triggers, make sure you subscribe to my youtube channel


Narcissistic abuse takes a terrible toll on your life. I’m Patricia, and my mother is a narcissist, so I know what you’re going through. These blog posts will help you understand narcissism better and give you tips for dealing with the narcissists in your life. Healing starts here!

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