Don't Lash Out
Vindictive, catty behavior between women thrives on reciprocity. You may be the victim now, but if you spread a counter rumor or engage in the game of dirty looks, you're just as guilty as the other woman, and you give her an excuse to become progressively meaner. The cycle of grown up mean girls truly is a cycle that spirals out of control, so allow that cycle to stop with you.

Be Friendly
Women often see other women as competition and sources of jealousy. So while you may think another woman has no reason to be mean to you, in her mind she might. Rather than just ignoring her, make an effort to reach out. Greet her with a smile, ask her about her family, or compliment her on something she's wearing. If you're nice to her, she has little incentive to continue being ugly to you.

Call Her On It
Some women are so used to interacting with other women in ways that are catty, vindictive, and mean-spirited that they may not be aware they're doing it. Mean girl behavior thrives on passive aggression, and it's hard for that aggression to remain passive if you call the other woman out on her behavior. Don't start a war and don't be ugly. But if there's a specific incident you can talk about, and being nice and friendly hasn't worked, confront the other woman and ask her if there's something that can be done to change the quality of your relationship. Some suggestions for how to start the dialogue:

"Hey, I've noticed that you roll your eyes a lot when I'm talking, and it hurts my feelings. I didn't know if you were aware that you were doing this, but I wanted to see if there was something I had done to offend you so we can have a better relationship."

"I feel like you don't like me. Have I done something to upset you?"

"I've heard that you are saying ugly things about me. This hurts my feelings and I want to have a good relationship with you. What can we do to fix this?"

Don't Take Undermining Behavior Lightly
Mean girls in school or on the job can undermine your performance and make your job impossible to perform. If you've tried the suggestions above and nothing has worked, start keeping a log of incidents, then go to your boss or professor with your concerns. It is important that, if a mean girl is trying to undermine you, your superiors know this is happening.

Mean girl behavior can only thrive when lots of women choose to participate, so don't do it! Stay out of that game and take the high road! And even if a few women have been mean to you, avoid adopting the belief that all women are mean or catty, or it's likely to make you behave like a mean girl too!