Looks like...

Mia Sara

I agree! I had to rewind stranger things the first time I saw her on it to make sure it wasn't Emmy Rossum. Even though it didn't make sense for Emmy Rossum to be playing a teenager

I just replied Emmy Russom to another thread lol. They resemble each other enough to be sisters.

True

This! Yes! I hope they okay sisters in the future!

Oops typo I meant *play sisters?

Yeah, a young Mia Sara.

I agree. She bears a resemblance to Mia Sara circa Ferris Bueller's Day Off. Pretty sure that's the look they were going for with her hair and makeup in Stranger Things.