Abstract: The pursuit of justice is a large part of the law of contracts, but in recent years most of the discussion about contract law has emphasized other values, such as freedom or economic efficiency. "Justice"-as used, for example, in the Restatement (Second) of Contracts-has become a flabby word denoting unexamined intuitions or random contingencies. This article tries to restore justice to its proper place in contract law by providing an analytic framework for discussing its role. It sets out five principles of justice embedded in contract law: (1) Justice as the equal exchange; (2) Justice as the honest wager; (3) Justice as the term that fits; (4) Justice as the deserved return; and (5) Justice as the advantage not to be taken. Each of these "Justices" responds to a distinct social sense of justice, and each helps explain a considerable swath of the actual law of contracts. But they are not always mutually consistent, so together they define a realm of debate rather than of demonstrable outcomes. The concluding section of the article looks at the mechanisms by which that debate works to produce results, and how it fits together with other forces also shaping the law.