What type of contracts are those in which only one party makes a legally enforceable promise?

Unilateral contracts are characterized by the fact that only one party makes a legally enforceable promise. This type of contract involves a situation where one party offers something in exchange for a specific action or performance by the other party. A common example of a unilateral contract is a reward offer; for instance, if someone promises to pay $100 to anyone who finds and returns their lost pet, the individual making the offer is the only one who has made a promise. The other party must perform the action—finding and returning the pet—to fulfill the terms of the contract.

In contrast, bilateral contracts require both parties to make promises to each other, creating obligations on both sides. Conditional contracts involve a performance that is contingent upon the occurrence of a specific event, while executable contracts refer more generally to contracts that are either executed or executable, lacking a unique definition in the context of promise-making. Understanding these distinctions helps clarify the nature of unilateral contracts and their role in legal agreements.