In Python, classes are fundamental building blocks of object-oriented programming (OOP). They serve as blueprints for creating objects, encapsulating data attributes and methods that define the behavior of those objects. By using classes, programmers can model real-world entities, making code more organized, reusable, and easier to maintain. Each class can have its own properties and functions, allowing for a structured approach to programming. The use of classes promotes encapsulation, inheritance, and polymorphism, which are key principles of OOP, enabling developers to create scalable and efficient software solutions. Understanding classes is essential for mastering Python programming.