Unlike other wedding-related celebrations, the engagement party has few very rules. Maybe it's because it's the first party out of the gate for a newly-engaged pair, so the etiquette goddesses decided to go easy on them. Even so, there are thing to keep in mind as you start planning your party. When it comes to whom to invite, it's up to the hosts (often the bride's parents), with the couple's input. Here are a few things to remember as you start building the guest list.
Narrow down the guest list.
Many brides and grooms want to keep the engagement party intimate, so they don't invite everyone they'll be asking to the wedding. They limit the guest list to their parents (and any stepparents), their grandparents, their siblings, their closest aunts, uncles, and cousins, the bridal party (if they've chosen them), and other beloved friends. Other couples restrict the party list to either their closest family members or their closest friends.
Though this option isn't common, some couples—because of the local custom or family obligations—invite their entire wedding guest list. If you do, give the engagement party a completely different look and feel from the wedding.
Have two parties.
Sometimes you'd prefer not to mix and match party guests. If you're up for it or multiple loved ones have offered to host a get-together in your honor, consider having two parties—one for family, the other for friends. (But don't invite any of the same people to both soirée.)
Don't be fickle.
If you're not inviting someone to your wedding, don't invite them to your engagement party. It would be awkward and rude because it implies they're only worthy of a pre-wedding party and not the main event.