Library Management System UML class diagram models a role-based architecture with User as the base class extended by Student, Librarian, and Admin entities. Students can search, borrow, return, and reserve books; Librarians approve requests and manage inventory; Admins oversee users and system configuration. The diagram captures relationships between Users, Books, Categories, Transactions, and Notifications, demonstrating inheritance hierarchies, foreign key constraints, and method responsibilities across all system actors. Fork this diagram to customize roles, add new user types, or extend transaction workflows for your institutional library platform. The design enforces separation of concerns and role-based access control, making it ideal for academic or enterprise library implementations.