OOPs Concepts in PHP: Go From Chaos to Clean Code

Object-Oriented Programming (OOP) in PHP helps you organize code into classes and objects, making development modular, scalable, and easier to maintain. By grouping related data and behavior, OOP allows for reusable and logical code structures that reflect real-world models.

Core principles such as encapsulation, inheritance, abstraction, and polymorphism simplify complex logic and enhance code clarity.

In this blog, we’ll explore the core OOPs concepts in PHP through practical examples, helping you write cleaner, smarter, and more efficient PHP applications.

Object-Oriented Programming (OOP) in PHP is a programming paradigm that structures code around objects rather than procedures. It emphasizes key principles like encapsulation, inheritance, abstraction, and polymorphism to build reusable, modular code. 

OOP helps developers model real-world entities, making code more intuitive and easier to manage. This approach enables the development of scalable, maintainable applications ideal for modern PHP development.

In 2025, professionals who know OOP concepts in programming will be in high demand. If you're looking to develop relevant programming skills, here are some top-rated courses to help you get there:

• AI-Driven Full-Stack Development Bootcamp
• Master of Design in User Experience
• Professional Certificate Program in Cloud Computing and DevOps

Here are five key features of Object-Oriented Programming (OOP) in PHP:

• Encapsulation: Encapsulation allows you to bundle data (properties) and methods (functions) that operate on the data within a class.
• Inheritance: Inheritance enables one class (child class) to inherit properties and methods from another class (parent class).
• Polymorphism: Polymorphism allows objects of different classes to be treated as objects of a common superclass. 
• Abstraction: Abstraction involves creating abstract classes or interfaces, which define methods that must be implemented by subclasses.
• Access Modifiers: PHP provides access modifiers like public, protected, and private to control the visibility of class properties and methods.

These features of OOP in PHP help create modular, reusable, and maintainable code, making it easier to scale and manage larger applications.

Also Read: What are the Advantages of Object-Oriented Programming?

Also Read: Understanding Encapsulation in OOPS with Examples

Also Read: Explore Object-Oriented Programming in Python 2025

Also Read: Master Polymorphism in OOP: Key Insights on Types & Examples

Now that you have a good understanding of main terms related to OOP, let’s look at the top OOP concepts you need to be familiar with.

Core OOPs Concepts in PHP with Examples

Object-oriented programming in PHP provides a structured approach to writing code that is modular, scalable, and easier to maintain. By focusing on creating reusable components and clear abstractions, PHP developers can build applications that are both flexible and robust, streamlining development and improving code quality across projects.

1. Classes & Objects

In PHP, a class is a template that defines properties (data) and methods (functions). You use it to create objects, which are actual instances holding their values. This is the core of object-oriented programming: defining reusable blueprints (classes) and generating individual versions (objects) that can operate independently with encapsulated behavior.

Sample code:

class Book {
  public $title;
  public $price;

  function setTitle($t){ $this->title = $t; }
  function getTitle(){ echo $this->title . "\n"; }
}

$b1 = new Book();
$b1->setTitle("PHP Mastery");
$b1->getTitle();

Code Explanation: You create a class Book with public properties and methods. The object $b1 is instantiated from the class and interacts with it using defined methods. The $this keyword is used to refer to the current object's context. Classes group logic, and objects bring them to life in your code.

Expected output:

PHP Mastery

2. Encapsulation (Access Modifiers)

Encapsulation is about restricting access to internal class data and allowing it only through controlled methods. PHP provides three access modifiers: public, protected, and private. Public elements are accessible everywhere, protected ones are accessible only within the class and its children. Private elements are accessible only within the same class. This helps you protect data and maintain integrity.

Sample code:

class User {
  private $email;

  public function setEmail($e){ $this->email = $e; }
  public function getEmail(){ echo $this->email; }
}

$user = new User();
$user->setEmail("you@example.com");
$user->getEmail();

Explanation: The email property is marked private, so direct access from outside the class is restricted. Instead, methods are provided to set and get its value. 

Expected output:

you@example.com

3. Inheritance

Inheritance allows you to create a new class based on an existing one. The new (child) class inherits the properties and methods of the base (parent) class. You can also add or override functionality as needed. This helps reuse code and organize related behavior efficiently across hierarchies.

Sample code:

class Book {
  public $title;
  function getTitle(){ echo $this->title . "\n"; }
}

class Novel extends Book {
  public $author;
  function getAuthor(){ echo $this->author . "\n"; }
}

$n = new Novel();
$n->title = "1984";
$n->author = "George Orwell";
$n->getTitle();
$n->getAuthor();

Explanation: Novel extends Book, meaning it inherits title and getTitle() from Book. It also adds its author and related method. This lets you build new functionality without duplicating code from the parent class, making code maintenance easier.

Expected output:

1984

George Orwell

4. Polymorphism (Overriding Methods)

Polymorphism enables objects of different classes to be treated through a common interface, with methods behaving differently based on the actual object. In PHP, you achieve this mainly through method overriding in inherited classes. This allows flexible code where the same method call adapts to the object’s class.

Sample code:

class Book {
  public $title;
  function getTitle(){ echo "Book: ".$this->title."\n"; }
}

class Novel extends Book {
  function getTitle(){ echo "Novel: ".$this->title."\n"; }
}

$b = new Book();
$b->title = "Basic Book";
$b->getTitle();

$n = new Novel();
$n->title = "Advanced Novel";
$n->getTitle();

Explanation: The Novel class overrides getTitle() from Book to change its output. When you use the method, PHP dynamically determines which version to call. This allows different classes to offer specific implementations while maintaining consistent interfaces.

Expected output:

Book: Basic Book

Novel: Advanced Novel

5. Abstract Classes

Abstract classes are part of OOPs concepts in PHP and act as partially defined templates. They allow you to define base methods while forcing child classes to implement specific methods using abstract declarations. Abstract classes cannot be instantiated directly as they are meant to be extended.

Sample code:

abstract class Shape {
  abstract public function area();
}

class Circle extends Shape {
  public $radius;
  function __construct($r){ $this->radius = $r; }
  public function area(){ return 3.14 * $this->radius * $this->radius; }
}

$c = new Circle(3);
echo $c->area();

Explanation: Shape defines an abstract method area() which all child classes must implement. Circle does that and calculates area based on radius. Abstract classes enforce a contract while allowing flexibility in how each subclass fulfills it.

Expected output:

28.26

6. Interfaces

An interface defines method signatures that implementing classes must fulfill. Unlike abstract classes, interfaces can't contain method bodies. PHP supports multiple interfaces per class, which is useful since multiple inheritance is not allowed with classes.

Sample code:

interface Logger {
  public function log($msg);
}

class FileLogger implements Logger {
  public function log($msg) {
    echo "Logging to file: $msg";
  }
}

$logger = new FileLogger();
$logger->log("Data saved");

Explanation: The Logger interface requires a log() method. FileLogger implements the interface and provides the method's body. This allows consistent method signatures across unrelated classes while still letting them behave differently.

Expected output:

Logging to file: Data saved

7. Traits

Traits are part of OOPs concepts in PHP that enable code reuse by allowing you to insert methods into multiple classes without using inheritance. They are ideal for sharing functionality between unrelated classes without creating a class hierarchy.

Sample code:

trait LoggerTrait {
  public function log($msg) {
    echo "Logging: $msg\n";
  }
}

class App {
  use LoggerTrait;
}

$app = new App();
$app->log("App started");

Explanation: The LoggerTrait defines a log() method. The App class uses it via use. Traits help keep code DRY and modular by letting you inject shared behavior into multiple classes without inheritance.

Expected output:

Logging: App started

8. Static Methods

Static methods are part of OOPs concepts in PHP, where the method belongs to the class itself rather than any object instance. They can be called directly using ClassName::method() and are helpful for utility functions or cases where maintaining object state isn't necessary.

Sample code:

class MathHelper {
  public static function square($x) {
    return $x * $x;
  }
}

echo MathHelper::square(5);

Explanation: square() is a static method, so you can use it without creating an object. It belongs to the class, and you access it using the scope resolution operator ::. Static methods are good for stateless, reusable logic.

Expected output:

25

9. Namespaces

Namespaces are part of OOPs concepts in PHP that help avoid name conflicts in larger projects by grouping classes, functions, or constants under a unique path. They are defined using the namespace keyword and accessed via use statements or fully qualified names.

Sample code:

namespace MyApp;

class User {
  public function sayHi() {
    echo "Hello from MyApp!";
  }
}

$user = new User();
$user->sayHi();

Code Explanation: The class User is part of the MyApp namespace. This avoids clashes with other User classes in different modules. Namespaces are crucial for organizing code and building scalable applications.

Expected output:

Hello from MyApp!

10. Final Keyword

The final keyword in PHP is used to restrict inheritance and method overriding. When applied to a class, it prevents that class from being extended. When used with a method, it prevents that method from being overridden in any subclass. This is useful when you want to enforce a specific behavior or lock down critical logic that should remain unchanged throughout the hierarchy.

Sample code:

class Animal {
  final public function speak() {
    echo "Animal speaks\n";
  }
}

class Dog extends Animal {
  // This will cause a fatal error
  // public function speak() {
  //   echo "Dog barks\n";
  // }
}

$d = new Dog();
$d->speak();

Explanation: The speak() method is declared final in the Animal class, which means subclasses like Dog cannot override it. If you uncomment the method in Dog, it will cause a fatal error. Using final ensures that specific functionality remains exactly as defined, preserving consistency or protecting sensitive logic from accidental changes.

Expected output:

Animal speaks

upGrad’s Exclusive Software and Tech Webinar for you –

SAAS Business – What is So Different?

Now that you understand the core OOP concepts in PHP, let’s move to the key principles of OOP.

Advanced OOPs Concepts In PHP

So far, we have learned some of the most popular OOPs concepts in PHP with examples. If you are looking for something more on the advanced level, don’t worry we have got you covered. The mentioned below list highlights some of the more advanced OOPs concepts in PHP.

• Protected Scope- As the name suggests itself, protected scopes are private, and can be accessed only through cloud accesses. It is very similar to private scopes, the only difference being private scope is accessible only to the exact class that has the property.
• Accessors And Mutators- Accessors, also sometimes referred to as getters, are functions that return the value of a class property. Mutators, on the other hand, are functions that change the value of a class property. Both these functions are especially useful when you are dealing with a large system or a complicated class. 
• The __get Method- There are certain methods that exist to make your class smarter. They are present in every class, but PHP handles them by default. One such method is the __get method. It is a simple accessor function that you can use when you want to get a property that does not exist. 
• The __set method- Completely opposite to the __get method, the __set method is used when your code tries to set a property that does not exist.
• The __construct method -Last but not least, yet another popular OOps concept in PHP is the __construct method. You can use this method when you want to create a new instance of a class or some really elegant code. Most of the time, this method is used to automatically run some extra code while the instance is created. 

Also Read: OOP vs POP: Difference Between POP and OOP

Next, let’s see how upGrad can help you improve your knowledge of OOPs Concepts in PHP.

Upskill with upGrad and Learn OOP

OOPs concepts in PHP lay the foundation for writing structured, reusable, and scalable code. Encapsulation, inheritance, abstraction, and polymorphism are key OOPs concepts in PHP. Understanding these principles is crucial for building efficient and maintainable web applications. A solid grasp of OOP in PHP also improves code quality, debugging, and real-world problem-solving.

Hands-on projects and real-world examples are essential for mastering PHP. upGrad’s programs build core PHP and OOPs skills for modern web development. Explore these additional courses to continue your learning:

• Introduction to Data Analysis using Excel
• Analyzing Patterns in Data and Storytelling
• Basics of Inferential Statistics
• Introduction to Tableau
• Case Study using Tableau, Python and SQL
• Node.js For Beginners
• React.js For Beginners
• JavaScript Basics from Scratch
• Core Java Basics

For personalized career guidance, contact upGrad’s counselors or visit a nearby upGrad career center. With expert support and an industry-focused curriculum, you'll be prepared to tackle programming challenges and advance your career.

Boost your career with our popular Software Engineering courses, offering hands-on training and expert guidance to turn you into a skilled software developer.

Explore our Popular Software Engineering Courses

Master in-demand Software Development skills like coding, system design, DevOps, and agile methodologies to excel in today’s competitive tech industry.

In-Demand Software Development Skills

Stay informed with our widely-read Software Development articles, covering everything from coding techniques to the latest advancements in software engineering.

Read our Popular Articles related to Software

Reference Link:

https://www.zend.com/blog/object-oriented-programming-php