AITA for telling my girlfriend to shut the f*ck up after she insulted my sisters thighs?

A Redditor shared his experience of defending his 12-year-old sister after his girlfriend made an insensitive comment about her body. The Reddit user, who has been caring for his sister due to family circumstances, was on a FaceTime call with his girlfriend when she remarked that his sister’s thighs were “kinda chunky.”

Enraged, he immediately told his girlfriend to “shut the f**k up” and ended the call. Now, his friends and family are accusing him of disrespecting his girlfriend, leaving him to question whether his reaction was justified. Read the full story below and share your thoughts.

‘ AITA for telling my girlfriend to shut the f**ck up after she insulted my sisters thighs?’

I’m 30 and my 12 year old sister is living with me right now because mom and pops are vulnerable so it made more sense for me to care for my sis for the time being.

She is a really great kid and tbh I feel in a lot of ways like she’s my own kid because my mom and dad don’t speak English so I kind of had to raise my sis in ways that they couldn’t. Hard to explain but I’m sure anyone with a secondary culture will get what I mean- my mom and dad are great parents but having an English speaking person to guide you through s**it when you live in an English speaking country is invaluable imo and my sister trusts me with stuff she won’t necessarily trust my parents with.

Anyway my girlfriend was FaceTiming me and my sister walked past in shorts and a t shirt cuz it’s hot. My ~~sister~~ gf waited til my sister had left the area ( but not the room) and made a face and said ‘maybe feed her less OP, her thighs are kinda chunky’

I saw red and told her to shut the f**ck up (just came out my mouth) and immediately ended the call. My sister is a bit chubby but ffs who says stuff like that about a 12 year old girl.
Literally. Everybody. I. Know. Has been texting me that I’m a POS boyfriend and that how can I disrespect my gf like that. I am expecting an apology from HER but to my shock everybody is expecting ME to apologize.
So Reddit, AITA?

Here’s what people had to say to OP:

snazarella says: NTA. 12 year old girls are incredibly vulnerable to body image issues. You’re absolutely right to shut down such comments immediately.

[deleted user] says: NTA and this is a huge red flag. Why would you want to date someone that insulted your little sister like that?

bgarth91 says: Huge NTA. Body shaming a 12 year old is a low move.

purplepeopleater205 says: NTA well done for standing up for your sister it’s talk like that, that no young girl should ever be judged on. I just hope she’s now your ex and that you never apologise!

Evolutioncocktail says: NTA. Your gf is a real piece of work for talking about a 12 y/o’s thighs. She needs to check herself.

puseyes says: NTA- Your gf was out of line and being a female, she should know how much those snide comments, no matter how well intentioned affect you FOREVER. You’re sister’s self confidence is more important than your girlfriend’s ego

GordonG47 says: NTA. At 12, girls bodies are all over the place. Making comments like that is just plain stupid. Your girlfriend needs to apologise, and so do all the half-wits that sent you text messages.
Now you know who your friends are, huh?

Chimom315 says: NTA!! Who says that about a 12 year old girl? Your girlfriend sounds like an awful and mean spirited person. If her friends are all defending her and coming down on you, then she has s**itty friends too. Your poor sister. I feel terrible for her. Find a girlfriend who will treat your sister as her own and love her just as you do.
Your girlfriend needs to go.

SupremeLeaderMeow says: ESH your girlfriend was wrong and rude and you were right to address it immediately and showing your sister support. but jesus christ talk about overreaction. Your girlfriend made an unwelcome comment about your sister, possibly thinking it would be between you two. She didn’t came to her face to b**lly her. You’re an adult, you should act like one.
Also wtf with those “wow HuuUuge red flag, burn bridges, break up, contact your lawyer” type comments. Evrything isn’t black or white guys.
Edit :spelling

andsometimesnot says: Feed her less?? Who talks like that about anyone? Who talks like that about a 12 year old? Who says that to their boyfriend about his kid sister? Your girlfriend is out of all sorts of lines! Do not apologise.

Could she be telling people a convenient version of the story that makes her sound better? I don’t see how anyone would see you as being the one in the wrong. NTA, your girlfriend is definitely TA.
Edited for typos and clarity

Was the Redditor right to stand up for his sister, or did he overreact in the heat of the moment? What do you think? Share your thoughts in the comments!