LDAP, or Lightweight Directory Access Protocol, is an open protocol used to access and manage directory information services over a network. It helps organizations store, retrieve, and organize user data such as usernames, passwords, and permissions in a centralized directory. LDAP is commonly used for authentication and authorization, allowing users to log in to various systems and applications with a single set of credentials. Its efficiency and interoperability make it a popular choice for managing access in corporate environments.