Viola – a shipwrecked young woman who disguises herself as “Cesario” so that she can join the court of Duke Orsino as his page. Olivia falls in love with this disguise of Viola. Viola disguised as a boy looks like her own twin brother. So, when Sebastian arrives, Olivia confuses him with the disguisedViola. Other characters who have met Cesario (Olivia in disguise) feel the same confusion when they see Sebastian.
Sebastian – Viola’s twin brother who is separated from her during the shipwreck. When he arrives at the court, the confusion of identity happens because, as a twin brother, his face is similar to Viola disguised as a man (Cesario).
(Viola and Sebastian are twins so they look like each other. When the sister is disguised as a male, she looks like her own brother.)
Duke Orsino – Duke of Illyria who loves Olivia.Olivia – a countess who is supposedly mourning the death of her father and brother. She has declared to not engage with anybody yet falls in love with Cesario who is actually Viola in disguise.
Antonio – a sea captain and friend to Sebastian.Valentine and Curio – gentlemen serving the Duke