Functional Programming is a programming paradigm that treats computation as the evaluation of mathematical functions and avoids changing state and mutable data. This approach emphasizes the use of pure functions, which produce the same output for the same input, making code easier to understand and test. In Functional Programming, functions are first-class citizens, meaning they can be passed as arguments, returned from other functions, and assigned to variables. This paradigm promotes a declarative style of coding, allowing developers to focus on what to solve rather than how to solve it, leading to more concise and maintainable code.