In computer networking, the Lightweight Directory Access Protocol, or LDAP, is a networking protocol for querying and modifying directory services running over TCP/IP. An LDAP directory follows the X.500 model: It is a tree of entries, each of which consists of a set of named attributes with values.

An LDAP directory typically reflects political, geographic, and/or organizational boundaries. LDAP deployments today tend to use Domain Name System (DNS) names for structuring the top levels of the hierarchy. Further below might appear entries representing people, organizational units, printers, documents, or anything else.