Technically (the best kind of correct), the female equivalent for Jungs would be Mädels, but it's hard to get right.
I'd only use it for a group of girls I'm a part of, and have only heard it used that way. Imagine: "Ich treffe mich heute mit meinen Mädels". (eng.: "I'm going to meet up with my girls.").
I hope this translates well enough to convey my impression that if somebody else uses it, it's inappropriately close language for somebody they may not know that good.