Whatsername
Whatsername, Whatshername, or What's-Her-Name may refer to:

Music
"Whatsername" (Green Day song)
Whatsername, a character from the American Idiot musical
"Whatshername", a song by Peter, Paul, and Mary from Album 1700
"Whatsername", a song by Deep Purple from Abandon
"Whatsername", a song by the Suicide Machines from On the Eve of Destruction: 1991–1995

Other uses
Princess What's-Her-Name, a character in Earthworm Jim

See also
Hazel Wassername, a character from 30 Rock
Placeholder name
What's Her Face (disambiguation)
What's His Name
What's My Name? (disambiguation)