How do you deal with a sibling who lies about you non-stop?

Perhaps understand where it comes from, sibling rivalry is as old as the hills. It often comes from a place of competition for attention. Who is she trying to impress when she does this? There is the key.

What a mess. Does the sibling lie about other things also? Not just sibling stuff. I can’t believe sibs do this. Is the sibling younger or older? All I can think is for you to always give credit to them when they do something great and be a very good example, don’t turn it into a competition or power struggle. When there is a way to prove they are lying, point it out to your parents. If your parents tell you they know your sib is exaggerating or lying, just know your parents are aware and try not to get too wounds up about it. How old are the siblings? If the lying sib is very young and the younger one, they might just grow out of it. it’s hard to be in the shadow of the cool older sister or brother. Kids are cool just be being older.

Are you still living in the same household?
My daughters were stuck in an unhealthy relationship. The younger is a people pleaser and the older took advantage of that by constantly manipulating her to do things to her advantage. She felt like she had to clear things like birthday party themes for her children and even her children’s names through her sister in order to not offend her.
It got so unhealthy that the younger daughter finally had to just make a break. They speak to each other st family gatherings and they do love each other but there is a big fat boundary between them now. The younger daughter had to break away to protect her sanity.
I know your situation is different but if your an adult you may need to just create some space between you and your sibling so she doesn’t know what’s going on in your life. She can’t twist facts she knows nothing about. (I’m assuming your sibling is a she.)

How old are you? Honestly, my brother did the same thing, and I kind of just shrugged all of it. In fact, my mom did it, too. If you don’t talk it out with him or her, then you either grow up or you’ll be like me and ignore what that person says. <—I do not recommend the latter approach.

I would show or tell my parents every time I had evidence he or she lied. I would call attention to whe I did a task at the time I did it. I would carry a secret tape recorder or video recorder and catch him or her in lies.

My sister used to do that in a sly, sneaky way. She wouldn’t flat out lie, but she’d make implications that suggested I was stupid, irresponsible and clueless. Her gig was that I was the oldest, and she wished she had that position. She also wanted to be the smartest person on earth.

When I met my future ex husband he had an 18 month old daughter. I accepted the child whole heartedly as my own. About 6 months after we married, he and I decided that he made enough to support all of us if I wanted to be a stay at home, mom, which I did. (We both worked at Boeing.) We were also working on getting me pg (took 3 years, as it turned out.)
My sister told a friend that I quit my job to be a stay at home mom, and I didn’t even have any kids! I said, “I have Jenny…..”
My sister said, “That’s not even your kid!”
It shocked me that she said that because she knew how I felt about the child.