A standard form contract (sometimes referred to as a contract of adhesion, a leonine contract, a take-it-or-leave-it contract, or a boilerplate contract) is a contract between two parties, where the terms and conditions of the contract are set by one of the parties, and the other party has little or no ability to negotiate more favorable terms and is thus placed in a "take it or leave it" position.

While these types of contracts are not illegal per se, there exists a potential for unconscionability. In addition, in the event of an ambiguity, such ambiguity will be resolved contra proferentem, for example, against the party drafting the contract language.

Theoretical issues.

There is much debate on a theoretical level whether, and to what extent, courts should enforce standard form contracts.

On one hand, they undeniably fulfill an important role of promoting economic efficiency. Standard form contracting reduces transaction costs substantially by avoiding the need for buyers and sellers of goods and services to negotiate the details of a sale contract each time the product is sold.

On the other hand, there is the potential for inefficient, and even unjust, terms to be accepted by signatories to these contracts. Such terms might be seen as unjust if they allow the seller to avoid all liability or unilaterally modify terms or terminate the contract. These terms often come in the form of, but are not limited to, forum selection clauses and mandatory arbitration clauses, which can limit or foreclose a party's access to the courts; and also liquidated damages clauses, which set a limit to the amount that can be recovered or require a party to pay a specific amount. They might be inefficient if they place the risk of a negative outcome, such as defective manufacturing, on the buyer who is not in the best position to take precautions.