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27 Horror Stories About Brothers-In-Law And Sisters-In-Law Who Were Just Unnecessarily Cruel

"When I came by to say goodbye, my SIL handed me a box containing every present I’d ever given her."

We recently asked the BuzzFeed Community to tell us the worst thing their sibling-in-law has done. Here are the wildest stories:

1. "My sister-in-law got COVID a week before her wedding and didn’t tell anyone. She got my parents and one side of grandparents (who all have health issues) sick because she wouldn’t move her wedding during a global pandemic."


2. "When my twins were born, my son was in the NICU. I hadn’t even gotten to hold my own baby yet. I was in recovery and my husband had sent my SIL pictures. My son was lying under a heat lamp with all sorts of tubes and wiring. She posted the pictures to Facebook before I even got to see them. I didn’t want pictures like that on social media. It’s a very private thing when you have a child in the NICU."


3. "My newly divorced ex-SIL borrowed the antique oak bed and new mattress set that was to be my daughter’s when she left her toddler bed. A month later, when she showed us the pics of her new bedroom set, I told her we’d come get my daughter’s bed back. She said, 'Oh! I threw it all away in the dumpster.'"

Cancel. Done. Starting Now.

woman making shocked face

4. "We told my SIL that we were planning to adopt from foster care. She waited until I left the room and told my husband that I'd ruin his life worse than his first wife did. She came to visit a few weeks later and tried to have an intervention to get us to stop adopting. She said I was ruining the family in front of my 4-year-old son. She constantly told us horror stories and flat-out lies to get us to change our minds. My husband started to distance himself from her (which she blamed me for) so when the adoption finally went through years later, he didn't tell her and she found out from MIL."

"She got mad at us for not sharing our joy with her. She wanted us to visit. I said we'd stay at a hotel close to her since we have four kids now and there wasn't enough room in her house for all of us. My MIL let me know that my SIL wanted our biological son to stay at her place when we go down there. That's it. Just our bio son but not the other kids."


5. "My youngest BIL has always hated me. Various things happened throughout the years, but the last straw was my husband’s funeral. We let everyone know that it would be a closed casket, because it was my husband’s request, but there would be family viewing before the regular viewing. Everyone came, even cousins, and I, a grieving widow, had to keep telling my BIL that if he waited, the casket would be closed. He did not come, so we had the family viewing and when the casket was shut, it became sealed. So guess who showed up the morning of the funeral mad because the casket was sealed?"

"After the funeral, he and his wife, who has apologized for all the things he did, came to the house, ate a bunch of food, and he then announced, like anybody cared, that the tiling of his kitchen wasn’t going to tile itself and started getting his coat. His wife was not ready to leave. She was embarrassed. I think this may have been a last straw for her because she left him a few months later."


confused faces from big little lies

6. "My SIL and I were pregnant at the same time and due the same week. She went into labor early, and her baby was in the NICU with serious health problems. We were all very worried, naturally. I called her the day after to check in on her and the baby, and she gleefully told me she had been waiting on my call 'because I knew I’d beat you and have my baby first!' Her preemie is in the NICU struggling to breathe, and she is gloating about 'beating me.' I was speechless."


7. "We recently lost my grandmother, and I kid you not, while my grandmother was dying, literally ONE HOUR from taking her last breath, my sister-in-law was reading through her will."

"To me, that seems like she only cares about one thing, so while her husband and the rest of us are about to lose someone so special, she was reading through papers not meant for her and holding back tears as she read all the stuff she would be getting by being married to my brother. I could go on, but to me, that changed my opinion of her forever."


surprised face

8. "My SIL met my youngest for the first time when he was 2 years old. She met him and decided she loved him so much that she wanted him. She called Child Protective Services on my husband and I. Child Services made an emergency call on us that night complete with a police escort. They found nothing wrong. She called them the next day asking if they apprehended my son so she could get custody of him."


9. "When we lost our daughter at 38 weeks gestation, my SIL told family members that I faked the pregnancy and our daughter never existed. I have pictures, her death certificate, and her ashes, but she insisted I was faking it all. We haven’t spoken to her since Emmalee died eight years ago, and life is SO much better without my SIL."


10. "My sister-in-law asked me to be her maid of honor when she got married. She also asked to wear my wedding dress. I said 'Of course' and was thrilled I meant that much to her. She had the wedding without telling me about it. She wore my dress and when it was returned to me, she had hemmed it with safety pins and there was dirt all over the bottom. I never got an apology but I did get called dramatic."


11. "My SIL and I had always had a tense relationship, but I tried to at least keep things polite. Among other things, I always made sure to buy her what I thought were thoughtful birthday and Christmas presents. About five years in, her family moved out of state for work. When I came by to say goodbye, my SIL handed me a box containing every present I’d ever given her, all unused and untouched."

"I haven’t wasted my time or money buying her presents since then. When I see my nephews, however, I’m always sure to have a very noisy or messy toy for them. THEY appreciate my gifts."


12. "I was very overweight at the time, and after a weekend visit, I had left some clothing at my in-laws' house. Well, their baby sister spilled the tea that my other sister-in-law posed in a pair of my pants like a 'before and after' weight loss picture."


confused face

13. "After an incredibly difficult year for multiple reasons — having my first child at 20 with my husband and, unbeknownst to me, dealing with postpartum depression — I landed in a hospital for my mental health. During said stay, my SIL informed my husband and his family that he could no longer be the best man or be any part of his brother’s wedding because 'Your wife is crazy.'"

"She used my illness as a young mother going through one of the toughest parts of my life as an excuse and said she felt threatened by my presence at her upcoming nuptials. Shortly after I was discharged and still trying to figure out how to mother my 6-month-old and care for myself, my husband was told, 'You should’ve never married her, otherwise this wouldn’t be a problem.' And yes, his family chose her side — 12 years later and we’re still treated like the outsiders, including our three children."


14. "My former sister-in-law announced MY pregnancy on social media before I got the chance to. She didn't even tag me in the post. I was so heartbroken. I knew this was going to be my only child, so I wanted to be able to make my own announcement."


15. "I found I was finally pregnant after trying for a while and surprised my in-laws at Christmastime with a box that had baby mittens in it. During the joy and hugging, my sister-in-law looked at us and said, 'Well I’m pregnant too.' She wasn’t."

"Her husband wasn’t even there when she shocked everyone with her false announcement. It went from happy to awkward to WTF real fast."


16. "My sister-in-law told my husband he could do better and to find someone else, while I was pregnant with our kid. Her wedding was the week after she did this. I backed out of the wedding and she called me crying and apologizing to save her ass. Nope. I definitely didn't want to be a part of her wedding party after that."


reproachful face

17. "My brother-in-law insisted on getting married in the middle of the coronavirus pandemic with no masks and a shared taco bar."

"I have severe asthma, so my husband and I were being extremely cautious. My husband was supposed to be a groomsman, so he offered a compromise: no mask on during photos, but we would both wear masks at all other times. My brother-in-law uninvited us and kicked my husband out of the wedding party."


18. "When my husband and I moved back to our hometown to be closer to family, we lived at my father-in-law's house while we were house hunting. My sister-in-law also lived there. One day, she stole multiple items of my clothing from our closet and SOLD THEM to one of those stores that buys gently used clothes and resells them. I only found out because she posted a picture of herself in something of mine on Instagram, which led me to looking in the closet and noticing things missing, then remembering she had just sold some stuff to said place."

"She denied doing it even though SHE POSTED herself in my clothes. She lied and said it belonged to a friend of hers who left it in her room. However, this romper had been purchased in a different city, several years beforehand when she was in middle school and wouldn't have been shopping at this store (nor would her friends have). She also lied about taking my other clothes and selling them even though we found another shirt of mine in her room."


19. "I fell behind on bills after my divorce and had to get a car title loan. I was working for my brother-in-law and renting a house from him. They paid me, but I was still short on rent and I fell behind on the car title loan. I tried to hide my vehicle for a few weeks until I could catch it up."

"My brother-in-law not only told the car title loan company where I hid my vehicle, but he was given a finder's fee for ratting me out after they successfully took my truck. I paid $6,000 for the truck and was only $200 behind on the loan."


oprah with hands up

20. "My brother-in-law made fun of my baby name choice before I had my son so much that I had to change it. He got my in-laws on board of making fun of it too. I love my son’s name now, but I’m still bitter about what a dick he was to a pregnant women."


21. "My sister-in-law actually gave us the opened and used items from her pantry for Christmas one year. Opened and used boxes of mixes, spices, and old canned goods. Another Christmas, she gave us two boxes of Girl Scout Cookies she had kept in her freezer from the March before."


confused face

22. "My sister-in-law accused me of being in love with my brother. When I asked my brother what made her think that, he said it was because I enjoy helping take care of his son, aka my nephew."

"So, in her twisted mind, the fact that I enjoy being in my nephew’s life must mean I’m in love with his father, my brother."


23. "My brother-in-law insisted on driving me, my mother, and his daughter to the other kid’s recital in one car. Despite multiple warnings about where my car was parked, he started to back up, floored it in reverse without a second glance in any of the mirrors, and nailed the bumper of my car."

"He demanded that we didn't go through insurance and that he would pay for the repairs out of pocket. By the time I had a listing of the repairs needed, he concluded that he wouldn’t have hit my car if I’d done a better job parking it and refused to cover the damage. Motherfucker caused $800 just in noticeable paint damage to my car and didn’t care how I felt about it because he didn’t mind the minor scuff his bumper took in the impact."


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24. "My fiancé and I got engaged in late 2015. We planned our wedding for summer 2017 so we could save up for the event and a house. March 2017 rolled around and my brother announced his girlfriend was pregnant and they were getting married in a small ceremony. Next day, he called and said SHE changed her mind and they were having a huge wedding instead so they 'don't miss out" and it would take place three weeks before OUR wedding."

"I wound up sharing my bridal showers, attention, and time with my sister-in-law because she didn't want to be 'showing' at her wedding. I mean, everyone could do the math. We all knew she was pregnant."


25. "My sister-in-law rescheduled her baby’s christening from February to the day my soon-to-be husband and I would leave for our honeymoon. We had to cancel our wedding due to COVID and since the honeymoon is the only thing that we are able to keep, the vacation meant so much to us. She said it shouldn’t be a big deal if we miss a day of our 'trip.'"


what face

26. "My sister-in-law and brother borrowed my mini freezer and then sold it. IT WASN'T HERS! It was a very big indicator of the type of person she was: materialistic, superficial, self-absorbed. She loved money and material things."


27. And "My sister-in-law — my brother's wife — told my husband, about a month after we got married, that we needed to consult her before we had any kids. My husband didn’t know her that well at the time and was very confused about the interaction. Five years later, when we did have a baby, she referred to my daughter as 'that child' after she was born. She refused to come see her and wouldn’t let my brother come see her either."

"They lived five minutes from us and my brother saw my daughter two times the first year of her life. They are now divorced."


Submissions have been edited for length and/or clarity.

What is the most annoying thing your sibling-in-law has ever done to you? Let us know in the comments.