Ok so my sister is 15 and I'm 21 but I live on the university campus. I visit my parents on the weekends and they always talk about how my sister acts, which is one of 4 things... Taking another family member's laundry from the washer/dryer and tossing it on the floor to wash hers. Eating someone else's marked foods or goods in the fridge. Expecting everyone else to do her chores (except for her laundry) and if not, she would get mad at them. And most recently she picked up the idea that because she's female and 15, my mom and dad should treat her like a princess and because she's female and 15, she thinks that anyone who tells her no or rebels against her demands hates her. It hasn't been just family either, she mostly treats her friends and their families as if she owns them and they have to pick up after her as well as treat her royally. Could someone please give any advise I can pass along to my parents? They are ashamed to have to ask themselves.

Yes, tell your parents to start being parents.

They are the reason she is doing this, they allow it to happen.

1. ground her.
2. take away phone, computer, games , music

If she makes clothes dirty, she has to re-wash.

If she does not do her chores, she is made to do them before she can do anything she wants.

So she wants to be treated like a princess, does not mean she gets to be.

Eating others food, OK I have an entire issue with "my food" "your food" so I will leave that alone, food in the house, would always be everyone's food in my home.

All right so the majority of the problem has been taken care of by sending her to an all girls school (I guess that's what they thought was best since not much was changing).

@Fr_Chuck Well, we didn't really have much of a "your food" "my food" thing, it was more like the next two examples. Before I moved on campus, I had a full time factory job and worked late into the night. My sister would eat the lunches I made myself for work, sometimes even just minutes before I would leave, she would be sneaking the remains in the trash.

I know that could be a "your food" "my food" thing, but the bigger thing was when my brother or I made sweets for school (the whole class party thing or whatnot) and we made enough for everyone to have one (or two) each. My sister, even though she knew she couldn't have any unless there were some not eaten, would eat some anyway and not care that there wasn't enough afterwards.

She's spoiled, plain and simple. I agree with Chuck, it's time your parents start acting like parents and punishing her when she misbehaves. Just because she demands to be treated like a princess, doesn't mean the adults around her have to give in to her demands.

She acts the way she acts because her parents let her get away with it. It's really as simple as that.