A Standard Library is a collection of pre-written code and functions that come with programming languages, making it easier for developers to perform common tasks. It provides tools for handling data, performing calculations, and managing input/output operations, among other functionalities. This allows programmers to focus on building their applications without having to write everything from scratch. Most programming languages, like Python, Java, and C++, include a Standard Library that is well-documented and widely used. By utilizing these libraries, developers can save time and reduce errors, as the code has been tested and optimized for performance.