AITA for Refusing to Co-Sign My Sister’s Mortgage After My Parents Went Behind My Back?

A Reddit user (28F) shared a dilemma where her parents pressured her into co-signing a mortgage for her younger sister (25F) after they made an offer on a house without consulting her. With no prior warning, the user was expected to co-sign due to her strong credit score, putting her own financial stability at risk.

Despite her refusal, the user faced backlash from her family, including accusations of selfishness and threats of future cutoffs. The user is now torn between protecting her finances and maintaining family harmony. Read the original story below for more on this challenging family situation.

‘ AITA for Refusing to Co-Sign My Sister’s Mortgage After My Parents Went Behind My Back?’

The article has the next update at the end.

I (28F) have been busting my b**t for years to save for my own house. I work in software, so I make decent money, but it still takes forever to build up a good down payment. Meanwhile, my younger sister (25F) is in grad school with barely any credit. Our parents (both mid-50s) found a house near them and decided she needs it. They made an offer—without telling me—and now the deal only goes through if I co-sign.

The problem? I had no clue they’d do this. My parents basically dropped a bomb: “You have the best credit score—co-sign so your sister can get the house!” They also hinted I should chip in for the down payment because “you’ve got the money.”

If I co-sign, I’ll be on the hook if my sister can’t pay. She’s still in school, has debt, and zero backup plan. The bank might also reject my future mortgage application since they’ll see I’m already tied to another loan. But my parents say I’m “selfish” and “forgetting family values.” My sister’s calling me a monster for leaving her “stranded,” and my mom threatened to cut off any future financial help (like wedding money) if I don’t help right now.

Some relatives think it’s insane my parents tried to rope me into this after they already made the offer. Others say I should just do it for “the family’s sake.” I feel guilty, but also mad they put me in this spot. AITA for protecting my own finances, or are they wrong for strong-arming me into co-signing a mortgage I never wanted in the first place?.

EDIT: I’m actually adopted lmao forgot to mention in my confused and angry state. My parents adopted me when I was very young because they’d been struggling to conceive. A few years later, they had my younger sister naturally, which was a huge deal to them—she was their “miracle baby.” Ever since, it’s felt like my role in the family became “the older, adopted one,” while she was the golden child who could do no wrong. Growing up, I was expected to pitch in more, be more responsible, and generally look out for my sister.

I worked my b**t off in school, snagged scholarships, and eventually landed a good job in software. All the while, I felt like my family mostly saw me as the “fallback option” in case anyone needed financial or emotional support. Now that I’m actually building my own life—saving for a house, focusing on my career—I’m realizing how my success just makes me look like a bigger piggy bank to my parents.

The more independent I become, the clearer it is that I need to separate myself from the constant guilt trips and the unspoken expectation that I’ll always bail them (or my sister) out. I love them, but I can’t keep sacrificing my own future to maintain a dynamic where I’m never the priority.

Update here: https://aita.pics/ZJvIu

Here’s the input from the Reddit crowd:

Independent-Stand351 −  Absolutely do NOT co-sign. NTA if you refuse. Let your Mom not pay for the wedding. If she’s threatening now, she will again.   In the end she probably won’t. But that’s not hhe main reason not to co-sign. The main reason is there is a huge chance you will be in debt for a house that is not yours. 

BadAdvice24_7 −  NTA, that sounds like a terrible idea. family soinds toxic. good luck.

celticmusebooks −  So, your sister is the Golden child and you are not. Don’t cosign the loan. Tell your parents to give your sister the wedding money and since your finances won’t be a dumpster fire (as they would if you cosign the loan) you’ll pay for your own wedding– and will be sure to send them a picture since obviously they won’t be there. Tell them how much you appreciate them freeing you from having to care for them as they age since that will fall 100% to your sister.
NTA but your family is really toxic.

Valuable_Actuary3612 −  Lock down your credit score and make sure they can’t use your information anyway. My sister had hers trashed by the EX because he would take out loans in her name. I have seen parents do this as well, regardless of the child’s age. Or consent.

Inner-Fisherman-9389 −  Terrible idea.. why does she need a house rn if she has barely any credit and she’s mid grad school.. an apartment sounds like what she needs.

she_who_knits −  Never ever cosign for anything for anyone. I don’t care who they are. NTA for following basic common sense.   Your parents demands are ridiculously unreasonable. 

Ej-mane −  Don’t do it.

GreenEyedPhotographr −  Mom, Dad, I’m not signing a f**king thing. My money and credit score are mine to do with what *I* choose. I choose **not** to do whatever this b**lshit is. If they don’t like it, tough s**t. Don’t play their games. Walk away knowing you’re going on to a better future.

teresajs −  NTA. You should NOT co-sign.  If you do, you would almost certainly be unable to buy your own house because your Available Credit would be reduced by the amount of your sister’s mortgage. Also, if you cosign, you would be legally responsible for the entire loan, plus fees, plus interest, but have no rights to any equity.  Also, as a cosigner, you wouldn’t have any method by which you could force your sister to remove your name from the debt.

In short, your family is trying to s**ew you over.  Don’t let them. Put a freeze on your credit immediately.  That should keep anyone from trying to borrow money in your name without your approval.  Refuse to cosign anything.  Don’t give them money. If some family members think your sister deserves support, tell them that Sis will be happy to hear that they are interested in helping her with house purchase expenses.