- Socrates is the main character of the dialogue who is responsible for guiding the direction of conversation with pointed questions throughout the enquiry. In the Laches,
as in almost all of Plato's dialogues, Socrates serves as the logical hero, who, unlike the others, rarely makes a mistake concerning the nature of courage. Rather, Socrates prefers to question the other characters through his technique of elenchus so as to make them wiser by demonstrating their lack of knowledge. At the conclusion of the dialogue, it is unanimously decided that Socrates will be chosen as an appropriate teacher for the children of Lysimachus and Melesias.
- Lysimachus is the character whose opening monologue begins the dialogue. He and his friend Melesias have gathered their friends Laches and Nicias to inquire of them whether or not they ought to teach their children the art of fighting in armor. They are looking to make honorable men of their children and want the advice of their friends since they are honorable men themselves and they have already raised children.
- Laches is a distinguished general who was sought after by Lysimachus and Melesias for advice in how to raise their children. He plays a major role in the dialogue, frequently offering his own opinion on matters or responding to claims made by Nicias or Socrates.
- Melesias is a friend of Lysimachus who plays a small part in the dialogue and wishes with Lysimachus to find a mentor for his son.
- Nicias is a general who Lysimachus has asked, with Laches, to help instruct his son and the son of Melesias. Nicias has very strong opinions throughout the dialogue and attempts to define courage as a kind of wisdom, which is the knowledge of the grounds of fear and hope.
- Aristides is the son of Lysimachus who is mentioned only once. He bears the name of his grandfather, Lysimachus's father. Lysimachus wishes that Aristides would live-up to his honorable name and motivates Aristides to seek the council of Nicias and Laches.
- Thucydides is the son of Melesias, and is mentioned only once. Like Aristides, he bears the name of his grandfather, which is why his father wants him to be brought up honorably.