Menaechmus of Epidamnus

The original Menaechmus was lost as a child during a visit to Tarentum. He goes into a crowd, and his father cannot locate him. Soon, a  wealthy merchant who lives in Epidamnus adopts him, and he lives there happily for many years; he grows up there, gets married, and engages in an affair with his neighbor. His wife is suspicious of him, and he claims to have fallen out of love with her. An angry man, the first Menaechmus punishes his wife for her anxieties by confirming them, and, when his brother returns for him, sells his “shrewish” wife on the market. Indeed, his love for her is fickle, but his love for his brother is long-lasting. 

Menaechmus of Syracuse

First known as Sosicles, the second Menaechmus changed his name out of respect for his missing twin brother. He grows up with his family in Syracuse, raised with stories of his lost brother. As such, he decides to travel the world to find his brother and embarks on a series of misadventures when people in Epidamnus believe he is his twin. Again, he is a loyal brother but a poor master, for it takes extensive effort on the original Menaechmus's part to convince his brother to free his slave, Messenio. The second brother is a dedicated man, although he is perhaps too dedicated, as his pursuit of his brother leads him to make poor choices that leave him financially insecure and out of his element.

Moschus

The merchant father of the Menaechmi, Moschus was a kind man with a big heart. Upon accidentally losing one of his sons in the bustling streets of Epidamnus, Moschus is broken, and his heart cannot bear the strain. His love for his sons proved his undoing, for he died of grief and left his second son fatherless.

Erotium

Erotium plays the role of the comical consort in the play; she is a beautiful woman who coyly toys with the original Menaechmus and easily wooed him away from his wife. After he gifts her his wife’s luxurious cloak, Erotium becomes a key player in the confusion, encountering both of the Menaechmi and punishing them for accidentally mistreating her. 

Messenio

A loyal slave, Messenio travels the world with his master, Menaechmus of Syracuse. He aids him in his mission to find his long-lost twin brother; along the way, he proves his mettle, saving his brother and his twin on numerous occasions and, ultimately, resolving the confusion about their parentage. At the end of the play, the Menaechmi agree to give him his freedom, and his loyalty proves worthwhile.

Matrona

Matrona is the wife of the original Menaechmus. She distrusts him and rages at him. When she discovers that he has given her cloak to Erotium, she insists that he get it back. On the street, she runs into his twin brother with the cloak and insists that he give it to her. Her father arrives, and together they decide to call the physicians when the person they think is her husband claims not to recognize either of them. Matrona is an anxious woman whose fears spoil her marriage and whose paranoia leads to its dissolution, as her husband coldly sells her on the market when he leaves Epidamnus. 

Peniculus

Peniculus is a man who gets patronage from Menaechmus of Epidamnus. He feels rebuffed when the second Menaechmus goes to dinner at Erotium's without him, believing that it is his friend who dined there. To retaliate, he tells Matrona about her husband's affair.

Cylindrus 

Erotium's cook, Cylindrus, is the first person to see the second Menaechmus in Epidamnum and the first to mistake one twin for the other, leading to the play’s chaos and confusion.