- The play's heroine. The orphan daughter of a great doctor, she is the ward of the Countess of Rousillon, and hopelessly in love with the Countess' son, Bertram. Her good qualities are attested to by nearly every character in the play, and events prove her a resourceful and determined woman, who is not easily discouraged by setbacks.
- The Count of Rousillon since the death of his father, and the Countess' only son. A handsome, well-liked young man, he proves to be an excellent soldier, but a cad in his relationship with Helena, who he unwillingly marries and quickly abandons.
- The mother of Bertram, the mistress of Rousillon, and Helena's guardian, she is a wise, discerning old woman who perceives Helena's worth and rejoices when she marries Bertram. When Bertram treats Helena badly, the Countess is quick to condemn his behavior.
King of France
- Bertram's liege lord. He is deathly ill when the play begins, and is miraculously cured by Helena, who uses one of her father's medicines. Like the Countess, he loves Helena, and is appalled by Bertram's behavior.
- An old French nobleman, who offers advice to the King and is friendly with the Countess. He is wise and discerning, perceiving both Helena's worth and Parolles' worthlessness.
- A companion of Bertram, he is a coward, a liar and a braggart, who pretends to be a great soldier when he is nothing of the sort. He is eventually exposed and disgraced.
- A genial French nobleman named Dumaine, he serves in the Florentine army and becomes friends with Bertram. Aware of Parolles' character, he and his brother, the Second Lord plot to expose him for what he is.
- The First Lord Dumaine's brother, similar in character and also a friend to Bertram.
- A young virgin in Florence, who Bertram attempts to seduce. She assists Helena in tricking him into sleeping with his lawful wife.
- A woman of Florence.
Duke of Florence
- The ruler of Florence, many French lords (including Bertram, Parolles, and Dumaine) volunteer to fight for him.
- An old servant of the Countess, who serves as a messenger and enjoys coarse, sexual humor.
- Another servant of the Countess.