Whether they are friendly or obnoxious, your boyfriend's sisters are a vital part of his life and you need to maintain a cordial relationship with them. It will be less stressful when you inevitably run into them if you get along. It can be difficult to establish a good relationship if your man's sisters are not very welcoming, but maintaining a pleasant attitude will help you deal with them.

Get to Know Them

Take the time to get to know your boyfriend's sisters. It is normal for them to be distant, cautious or even hostile at the beginning of your relationship, but they will probably warm up to you once they get to know you better. Plan activities with them so you can bond. If you want to develop a good relationship with them, invest the time and make the relationship one of your priorities. This will show them that you truly care about their brother and want to become friends with them.

Be Understanding

Don't expect your boyfriend's sisters to love you overnight. In fact, you might experience some resistance or jealousy from them at first. Understand that these feelings probably stem out of concern and love for their brother. His sisters may also experience some resentment toward you because they can't spend as much time with their brother as they did before you were in the picture. Encourage them to join you and your boyfriend on outings so they can spend time with their brother. Don't be possessive of your boyfriend, and motivate him to spend quality time with his sisters without you. Their concerns will be appeased once they realize how much you love and care for their brother.

Kill Them with Kindness

Be nice to your boyfriend's sisters even if they are not nice to you. You've probably heard the saying "kill them with kindness." Dissipate their hostile feelings by going out of your way to be nice to them. In the "Proceedings of the National Academy of Sciences," James H. Fowler and Nicholas A. Christakis report their findings that kind and cooperative behavior is contagious and that people who witness kind behavior are more likely to be kind themselves. Maintain a pleasant attitude when interacting with your boyfriend's sisters, even if they are unfriendly and rude. Your friendly attitude will make it harder for them to remain hostile.

Take a Step Back

Recognize when it's time to keep your distance. If you've tried everything and your boyfriend's sisters remain unfriendly, accept the fact that you might never become close friends. Focus on maintaining a cordial relationship and avoiding conflict. "Agree to disagree" with them. Sometimes its best to keep a distance; trying too hard to establish a relationship with them can result in family conflict.