Top Python OOP Interview Questions and Answers (2026)

Object-Oriented Programming (OOP) is one of the most important concepts in Python and is frequently asked in technical interviews. Whether you’re a fresher or an experienced developer, a strong understanding of Python OOP concepts is essential for clearing coding interviews and building scalable applications.

In this article, we’ll cover the most commonly asked Python OOP interview questions along with detailed answers and examples.

1. What is Object-Oriented Programming (OOP)?

Object-Oriented Programming (OOP) is a programming paradigm that organizes code using objects and classes.

OOP helps developers:

  • Improve code reusability
  • Reduce code duplication
  • Increase maintainability
  • Build scalable applications

Python supports OOP through classes and objects.

Example:


class Student:
    pass
student = Student()

2. What are the four pillars of OOP?

The four main principles of OOP are:

  1. Encapsulation
  2. Inheritance
  3. Polymorphism
  4. Abstraction

These concepts help create modular and reusable code.

3. What is a Class?

A class is a blueprint for creating objects.

Example:


class Car:
    def start(self):
        print("Car Started")

The class defines attributes and methods that objects can use.

4. What is an Object?

An object is an instance of a class.

Example:


class Car:
    pass
car1 = Car()
car2 = Car()

Here, car1 and car2 are objects of the Car class.

5. What is the difference between a Class and an Object?

Class Object
Blueprint Instance
Logical entity Physical entity
Defines structure Uses structure
Created once Multiple objects possible

Example:


class Student:
    pass
student1 = Student()

6. What is the init() Method?

The __init__() method is a constructor in Python.

It is automatically called when an object is created.

Example:


class Student:
    def __init__(self, name):
        self.name = name
student = Student("John")

7. What is self in Python?

self refers to the current object of the class.

Example:


class Student:
    def __init__(self, name):
        self.name = name

Without self, instance variables cannot be accessed within the class.

8. What are Instance Variables?

Instance variables belong to individual objects.

Example:


class Student:
    def __init__(self, name):
        self.name = name

Each object can have different values.

9. What are Class Variables?

Class variables are shared among all objects of a class.

Example:


class Student:
    school = "ABC School"

All objects access the same variable.

10. Difference Between Instance Variable and Class Variable

Instance Variable Class Variable
Belongs to object Belongs to class
Unique value Shared value
Uses self Defined directly inside class

Example:


class Student:
    school = "ABC"
    def __init__(self, name):
        self.name = name

11. What is Inheritance?

Inheritance allows one class to acquire properties and methods from another class.

Example:


class Animal:
    def speak(self):
        print("Animal Sound")
class Dog(Animal):
    pass

Dog inherits the speak() method.

12. What are the Types of Inheritance in Python?

Python supports:

  • Single Inheritance
  • Multiple Inheritance
  • Multilevel Inheritance
  • Hierarchical Inheritance
  • Hybrid Inheritance

13. What is Method Overriding?

Method overriding occurs when a child class provides its own implementation of a parent class method.

Example:


class Animal:
    def sound(self):
        print("Animal Sound")
class Dog(Animal):
    def sound(self):
        print("Bark")

14. What is Polymorphism?

Polymorphism allows the same method name to behave differently.

Example:


class Dog:
    def sound(self):
        print("Bark")
class Cat:
    def sound(self):
        print("Meow")

Both classes use the same method name.

15. Does Python Support Method Overloading?

Python does not support traditional method overloading like Java or C++.

Instead, default arguments can be used.

Example:


class Demo:
    def add(self, a, b=0, c=0):
        return a + b + c

16. What is Encapsulation?

Encapsulation is the process of wrapping data and methods into a single unit.

Example:


class BankAccount:
    def __init__(self):
        self.__balance = 1000

Data is protected from direct access.

17. What is Data Hiding?

Data hiding restricts access to internal data.

Example:


class Employee:
    def __init__(self):
        self.__salary = 50000

Double underscores make variables private.

18. What is Abstraction?

Abstraction hides implementation details and shows only essential features.

Example:


class Vehicle(ABC):
    @abstractmethod
    def start(self):
        pass

19. What is an Abstract Class?

An abstract class cannot be instantiated directly.

Example:


from abc import ABC
class Shape(ABC):
    pass

20. What is an Abstract Method?

An abstract method is declared without implementation.

Example:


@abstractmethod
def calculate_area(self):
    pass

Child classes must implement it.

21. What is Multiple Inheritance?

A class inherits from multiple parent classes.

Example:


class A:
    def show(self):
        print("A")
class B:
    def display(self):
        print("B")
class C(A, B):
    pass

22. What is MRO (Method Resolution Order)?

MRO determines the order in which parent classes are searched.

Example:


class A:
    pass
class B(A):
    pass
print(B.mro())

Output:

[B, A, object]

23. What is the super() Function?

super() allows access to parent class methods.

Example:


class Parent:
    def show(self):
        print("Parent")
class Child(Parent):
    def show(self):
        super().show()
        print("Child")

24. What are Static Methods?

Static methods belong to the class and do not access instance variables.

Example:


class Math:
    @staticmethod
    def add(a, b):
        return a + b

25. What are Class Methods?

Class methods work with class variables.

Example:


class Student:
    school = "ABC"
    @classmethod
    def get_school(cls):
        return cls.school

26. Difference Between Static Method and Class Method

Static Method Class Method
Uses @staticmethod Uses @classmethod
No cls parameter Uses cls parameter
Independent of class data Accesses class data

27. What are Magic Methods?

Magic methods are special methods surrounded by double underscores.

Examples:


__init__()
__str__()
__len__()
__add__()

28. What is the str() Method?

The __str__() method returns a readable string representation of an object.

Example:


class Student:
    def __str__(self):
        return "Student Object"

29. What is Composition in OOP?

Composition means creating complex objects using other objects.

Example:


class Engine:
    pass
class Car:
    def __init__(self):
        self.engine = Engine()

A car “has an” engine.

30. Difference Between Inheritance and Composition

Inheritance Composition
IS-A relationship HAS-A relationship
Tightly coupled Loosely coupled
Extends functionality Combines functionality

31. What is Operator Overloading?

Operator overloading allows operators to work with custom objects.

Example:


class Number:
    def __init__(self, value):
        self.value = value
    def __add__(self, other):
        return self.value + other.value

32. What is Duck Typing?

Duck typing focuses on behavior rather than object type.

Example:


class Dog:
    def speak(self):
        print("Bark")
class Cat:
    def speak(self):
        print("Meow")

Both can be treated similarly because they implement the same method.

33. What is Aggregation?

Aggregation is a special type of composition where objects can exist independently.

Example:


class Teacher:
    pass
class School:
    def __init__(self, teacher):
        self.teacher = teacher

34. Why is OOP Important?

Benefits include:

  • Reusability
  • Modularity
  • Maintainability
  • Scalability
  • Security
  • Easier debugging

35. Which OOP Concept Provides Code Reusability?

Inheritance provides code reusability because child classes can reuse parent class methods and attributes.

36. Which OOP Concept Provides Security?

Encapsulation provides security by hiding sensitive data from direct access.

37. Can We Create an Object of an Abstract Class?

No.

Abstract classes are incomplete and must be inherited before use.

38. What is Constructor Chaining?

Calling parent constructors from child constructors.

Example:


class Parent:
    def __init__(self):
        print("Parent")
class Child(Parent):
    def __init__(self):
        super().__init__()
        print("Child")

39. What is the Difference Between Public, Protected, and Private Members?

Access Modifier Syntax Accessibility
Public name Anywhere
Protected _name Class & Child
Private __name Inside Class

40. Why is Python Considered an Object-Oriented Language?

Python supports:

  • Classes
  • Objects
  • Encapsulation
  • Inheritance
  • Polymorphism
  • Abstraction

These features make Python a fully object-oriented programming language.

Conclusion

Object-Oriented Programming is one of the most important topics in Python interviews. Most interviewers ask questions related to classes, objects, inheritance, polymorphism, encapsulation, abstraction, constructors, method overriding, static methods, class methods, and design principles. Understanding these concepts thoroughly and practicing coding examples will help you confidently answer Python OOP interview questions in both fresher and experienced-level interviews.

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