Do I buy for both?

[albatros]

DD1 has been invited to a joint birthday party for two sibblings one is in her class and the other is 2 years older and dd1 dos not know her. Should I buy a little present for the older sister as well as the one my dd knows?

I wouldn't, I presume the younger sibling will be getting birthday presents from the children invited on her behalf

sorry, I meant older sibling.

I would!

Just the one your DD knows.

The invite dos not say birthday but I am assuming that it is, just says dd1 is invited to and *** party. their birthdays might be in the holidays I am not sure and I do not know the parents. I think I might just buy a little something for the elder one incase it is a party for them to make friends.

If it's not stated then I'd buy just a very small token gift and a card for the older sibling - or something they could share?

They should really let you know if you are only expected to buy for one - that's what we did when ds1 had a joint party this year with a little girl in his class.