1. Agency refers to a department of a local or national government responsible for the oversight and administration of a specific function, such as a customs agency or a space agency. Examples within the United States government include the Federal Emergency Management Agency and the Central Intelligence Agency.
2. Agency is an area of law dealing with a contractual or quasi-contractual relationship between at least two parties in which one, the principal, allows the other, the agent, to represent her or his legal interests and to perform legal acts that bind the principal. Agency can be created in a variety of ways, such as through the grant of a power of attorney also known as a mandate in civil law jurisdictions, it can also be implied from the conduct of the parties.

The law of agency is used in many professional areas, from contract negotiation (business management), employment procurement (i.e. modelling agencies), by financial advisors, in the buying and selling of real estate, the negotiation of entertainment and sports deals and in many day to day transactions where one person (the "agent") is allowed to stand in for another individual to fulfill their wishes. Agents can represent the interests of one party, or they may represent the interests of several, conflicting or potentially conflicting parties. In the case of such dual agency the agent must either disclose information received by one party to the other or act in a limited agency capacity to prevent a situation where the agent's loyalty to the multiple principals is compromised.

See also: List of Hollywood agencies and management companies