Vintage Skipper Masquerade
Yellow and Black Short Dress with Black Tulle Trim
Barbie and Ken had matching costumes. Barbie's is Masquerade #944 (1963-1964) .
Although Barbie and Skipper's outfits look almost the same, Barbie's is a one-piece with a halter-type top that ties in the back and Skipper's is a 2-piece dress with sleeves and snap closures in the back.
This ensemble is fairly easy to find - the Black Panties will frequently have problems with the elastic in the waist. The Invitation is very hard to find.