AITA for refusing to help my sister with her wedding because she never showed up for mine?

A woman who invited her sister to her wedding two years ago — even giving her a special role — was devastated when the sister RSVP’d yes but didn’t show up, offered no apology, and told her to “get over it.” Now the sister is planning her own wedding and expects the woman’s help with planning, financial support, and even borrowing decorations.

The woman refused, saying she won’t invest in someone who couldn’t bother to support her on her big day. The sister calls her petty and bitter; their parents are pressuring her to “be the bigger person” and let it go. Is she the asshole for standing her ground?

‘AITA for refusing to help my sister with her wedding because she never showed up for mine?’

The sisters were never very close but remained civil:

Now the sister is getting married and expects help:

Reciprocity is a cornerstone of healthy family relationships. When someone repeatedly fails to show up for important events (like a wedding) and offers no real apology, it erodes trust and respect. The sister’s expectation of help, money, and resources for her own wedding — after ghosting OP’s — is entitled and one-sided.

The phrase “be the bigger person” is often weaponized against those who set boundaries, especially women in family dynamics. It’s okay to protect your energy and not reward poor behavior with generosity. Saying “no” isn’t petty — it’s self-respect.

According to family therapist Dr. Harriet Lerner, author of The Dance of Anger, “When someone repeatedly disrespects your boundaries or fails to show up, withholding support isn’t revenge — it’s a natural consequence. Healthy relationships require mutual care, not one-sided giving.” (Source: her work on family boundaries and resentment.)

OP should continue to hold her boundary. If parents pressure her, she can calmly explain she’s matching the energy her sister gave. Therapy could help process the hurt, but she’s not obligated to help plan or fund the wedding.

These are the responses from Reddit users:

The Reddit community overwhelmingly supported the OP (NTA), agreeing that she is not obligated to help her sister after being completely ghosted and dismissed on her own wedding day. Most people called the sister entitled and selfish, and praised OP for setting healthy boundaries.

Most called the sister entitled and selfish, and praised OP for setting healthy boundaries:

Several emphasized that the sister’s behavior was disrespectful and that OP is simply matching her energy:

Many suggested practical ways to respond and protect her peace:

This story is a classic example of one-sided expectations in family relationships. The sister showed zero regard for OP’s wedding day — no apology, no effort — but now demands time, money, and support for her own. OP is not obligated to be the “bigger person” or reward poor behavior. Saying no is healthy boundary-setting, not pettiness. Parents pressuring OP are enabling the sister’s entitlement.

What do you think? Was she too harsh in refusing to help, or is she right to stand her ground? Have you ever dealt with a sibling who only shows up when they need something? Share your thoughts below!