The History of the Peloponnesian War is an account of the Peloponnesian War in Ancient Greece, fought between the Peloponnesian League (led by Sparta) and the Athenian league (led by Athens). It was fought over 20 years. It was written by Thucydides, an Athenian general who served in the war. It is widely considered a classic and regarded as one of the earliest scholarly works of history. The History was divided into eight books by editors of later antiquity.

Analyses of the History generally fall into one of two camps. On the one hand are those who view the work as an objective and scientific piece of history. The judgement of J. B. Bury reflects this traditional interpretation of the work: "[The History is] severe in its detachment, written from a purely intellectual point of view, unencumbered with platitudes and moral judgements, cold and critical." A more recent interpretation, associated with reader-response criticism, argues that the History is better understood as a piece of literature than an objective record of the past. This view is embodied in the words of W. R. Connor, who describes Thucydides as "an artist who responds to, selects and skillfully arranges his material, and develops its symbolic and emotional potential." The former outlook views Thucydides as pathbreaking, modern, and philosophical, ahead of his time; the latter views the historian as closely connected with his historical and cultural context. Both interpretations are accepted by scholars, sometimes by the same scholar, and seem to capture the contradictory impulses and tensions within the History.