According to the books, she doesn't remember her last name.
Brandon . Full name = Mary Alice Brandon , changed to Alice Cullen when she joined Carlisle`s coven / The Cullen Coven .
Cynthia
her name is Cynthia :)
Mary Alice Brandon
Cynthia
Mary then her middle name was Alice
Cynthia Brandon
Alice Nelson
Alice had a little sister named Cynthia. Alices sister's name is Cynthia Brandon. In New moon Cynthia's daughter (alice's neice) is still alive.
Alice Cullen or Mary Alice Brandon was her human name.
Hale. and why? it is because if alices and jaspers last name was the same that would be weird because they are dating. and because he looks like rosalie and rosalie wanted to keep her last name hale because it was what she had when she was human. they are supposed to be twins.
Mary Alice Brandon (Answer from www.twilightlexicon.com).
Alice's sister's full name while she was human in Twilight was Cynthia Brandon.