The Laches is a Socratic dialogue written by Plato. Participants in the discourse present competing definitions of the concept of courage.

In this dialogue, Socrates and Theaetetus discuss three definitions of knowledge: knowledge as nothing but perception, knowledge as true judgment, and, finally, knowledge as a true judgment with an account. Each of these definitions is shown to be unsatisfactory.

The work puts forward speculation on the nature of the physical world and human beings and is followed by the dialogue Critias.