User Interface Frameworks are collections of pre-written code and tools that help developers create user interfaces for applications more efficiently. They provide a structured way to design and implement visual elements, such as buttons, menus, and forms, ensuring consistency and usability across different platforms. Popular examples include React, Angular, and Vue.js. These frameworks often come with built-in components and libraries, allowing developers to focus on functionality rather than starting from scratch. By using a framework, developers can save time, reduce errors, and enhance the overall user experience of their applications.