She had no real sisters, only two wicked and ugly step sisters; Anastasia and Drizella.
In a great many of the older versions, for example those collected in Marian Cox's book of 345 Cinderella variants, the heroine had only one stepsister; and this girl was sometimes pretty (at least...
Anastasia Tremaine Drucilla Tremaine
They are mean and ugly and very, very jealous of Cinderella.
The names of Cinderella's step-sisters are Anastasia and Drizella.