Which cousins should I invite?

Though most etiquette advisors will say that inviting one of your first cousins means you should invite them all, this rule does not mean you must treat both sides of the aisle the same.

Elizabeth Howell of the Emily Post institute confirms: It's best to treat each family according to the closeness (and the reality) of that family's ties. Your family won't be as aware of the family-tree breakdown on his side; but should they discover that his first cousins were included while yours were not, there's a simple reply: "His family is much closer than ours is."