Object-Oriented Programming (OOP) is a crucial subject in the second semester of BSc.CSIT, focusing on the principles of object-oriented design and programming. The course covers key concepts such as classes and objects, inheritance, polymorphism, encapsulation, abstraction, constructors, and file handling. OOP enhances code reusability, scalability, and maintainability, making it essential for software development. Understanding OOP is fundamental for mastering modern programming languages like Java, C++, and Python.