I know, I know

1ofThoseDays

You guys get a million invitation questions a day, but I couldn't find this one.  My wedding is still a little bit off, but I have a question about the outer addressing of an invitation.  My sister, her boyfriend, and their two children are invited to the wedding.  Do I need to write out the children's names or can I put that on just the inside?  Just so everyone knows, I'm not sending the invitations yet, I was just wondering for future reference.
Also, because me niece is in the bridal party, I was told I need to send her a separate invitation, is this true?
Edit- Clarification

salt78

You can just put "and Family". 

ETA: And no I don't see why she would need a separate invite. 

doctabroccoli

You could just say "and family". 

ETA:  Blah, Salt beat me to it.

lyndausvi

you can do 'and family' on the outer or add their names to the inner envelope (if you are having one).  Either way is fine.

You don't have to give the niece a separate invite.  But if you have an extra (I know I did) it's a nice thought.

squirrly

I'm going to veto the "and family" suggestion.  It gives them the opportunity to bring anyone they deem to be family.

You only need to send one invitation to the family, but you certainly CAN send your niece a separate one if you like. 

Assuming that the kids are both under 18, the invitation should be addressed as such:

Outter:

Ms. Sister Last
Mr. Boyfriend Last
Address


Inner:
Ms. Last
Mr. Last
Miss Oldest Niece
Miss Youngest Niece

1ofThoseDays

I was thinking about putting names on the RSVP card with meal options, would that be acceptable?

salt78

I see Squirrly's point as far as the "and Family" is concerned...but I would think that because it's your sister that she would know what you meant. (It would be different if it were some rando.)

doctabroccoli

In Response to <a href="http://forums.theknot.com/Sites/theknot/Pages/Main.aspx/wedding-boards_etiquette_i-know-i-know?plckFindPostKey=Cat:Wedding BoardsForum:9Discussion:3910a952-e825-48e0-8f61-93637f41fe0ePost:2de8389a-aada-46b3-be13-c6834d85221d">Re: I know, I know</a>:
[QUOTE]I was thinking about putting names on the RSVP card with meal options, would that be acceptable?
Posted by 1ofThoseDays[/QUOTE]

Completely!

Squirrly - I never thought about the "and family" thing that way, I guess mostly because FI and I are the oldest of our generation, so there aren't more than a couple invites that require "and family".

1ofThoseDays

So it's okay to put just
Ms. Bride's sister
Mr. Sister's Boyfriend
on the invitation but for the RSVP and meal choices put
Ms. Bride's Sister
Mr. Sister's Boyfriend
Miss. Favorite Niece
Mr. Baby Boy
Is the abbreviation the same for Mister and Master?

Calypso1977

i was always taught that if you had inner envelopes, you put on the outside:

Mr. and Mrs. John Smith

and on the inside:

Mr. and Mrs. Smith
Miss Sally Smith
Mr. Jason Smith

tidetravel

Kids names should be listen on the inner envelope, if you have one.

squirrly

You need their names on the envelope, not just the RSVP card. 

Calypso, the adult guests aren't a married couple.

1ofThoseDays

Okay, thank you!

TurtlesAllTheWayDown

In Response to <a href="http://forums.theknot.com/Sites/theknot/Pages/Main.aspx/wedding-boards_etiquette_i-know-i-know?plckFindPostKey=Cat:Wedding%20BoardsForum:9Discussion:3910a952-e825-48e0-8f61-93637f41fe0ePost:3a528cb4-9620-42c6-a9df-c9e28e6c53b2">Re: I know, I know</a>:
[QUOTE]So it's okay to put just Ms. Bride's sister Mr. Sister's Boyfriend on the invitation but for the RSVP and meal choices put Ms. Bride's Sister Mr. Sister's Boyfriend Miss. Favorite Niece Mr. Baby Boy<strong> Is the abbreviation the same for Mister and Master?</strong>
Posted by 1ofThoseDays[/QUOTE]

Technically, there's no abbreviation for Master. You can spell it out.