Orsino: Duke of Illyria who unsuccessfully woos Olivia only to find his true love in Viola
Sebastian: Viola's twin sibling (brother) who, mistaken for Cesario, Olivia marries
Antonio: Sebastian's friend who saves Sebastian from drowning
Sea Captain: the captain whose ship brings Viola to the coast of Illyria and who helps Viola disguise herself as Cesario
Valentine and Curio: gentlemen attending on the Duke
Sir Toby Belch: Olivia's uncle, he is a chronic drunkard and troublemaker
Sir Andrew Aguecheek: Sir Toby's friend who isn't particularly bright or brave
Malvolio: Olivia's steward whose sanctimonious piety rubs most people the wrong way
Feste: Olivia's deceased father's personal jester who Olivia has inherited and who is valued by many for his wit and entertaining ways
Fabian: Olivia's servant who is one of the principle schemers in making Malvolio look like a fool
Olivia: a rich countess who falls in love with Cesario, unware that he is really Viola, a she
Viola: Sebastian's twin sibling (sister) who loves Orsino but is compelled to plea for Olivia's love on behalf of Orsino
Maria: Olivia's gentlewoman who forges a letter in her lady's handwriting to fool Malvolio