Okay here is my question... is it proper ettiquette to invite your brothers wife's family to your wedding?? My sister in laws family... brothers sisters and parents... do I have to invite them to my wedding according to proper ettiquette?

First, decide on how many guests you will invite. Are you sending invitations for only the wedding, and other invitations for the wedding and the reception?

Anyone off the street can attend the wedding, invitation or not. You will have a bride's total for the reception. Do you like your brother's wife's family and want to invite them?

No, they don't have to be on the bride's reception list.

The thing is our families don't really get along but I have been told it is proper

No. There is no etiquette that dictates what guests you must invite. Obviously the usual thing that people do is invite immediate family on both sides. That means your family and your fiance's family. That doesn't include extended family, which would be your sister in laws family members. If this helps in the discussions, I am sure you have heard of people not inviting their own brother, sister, or one parent due to family issues/arguments. It really is up to the bride and groom who they want in attendance on their happy day. I know people who didn't invite their own cousins due to financial constraints. No biggie. So, if cousins don't have to be invited, why should a sister-in-laws extended family be invited? Sounds like someone is trying to create a rift.

By the way, Congratulations on your impending marriage! :)

Ruby is correct, there is no reason you should invite them per ettiquette.

My husband's brother was his best man, his nephew was the ring bearer and his niece was the flower-girl... now, the sister-in-law walked her son (the ring bearer) down the aisle... he's 2... and so she was there. However, we didn't invite her family. We didn't feel it was necessary.