In [[object-oriented programming]] such as is often used in [[C++]] and [[Object Pascal]], a '''virtual function''' or '''virtual method''' is an inheritable and [[Method overriding (programming)|overridable]] [[function (computer science)|function]] or [[method (computer science)|method]] that is [[dynamic dispatch|dispatched dynamically]]. Virtual functions are an important part of (runtime) [[Polymorphism (computer science)|polymorphism]] in [[object-oriented programming]] (OOP). They allow for the execution of target functions that were not precisely identified at compile time.
Most programming languages, such as [[JavaScript]], [[PHP]] and [[Python (programming language)|Python]], treat all methods as virtual by default<ref>{{Cite web|title=Polymorphism (The Java™ Tutorials > Learning the Java Language > Interfaces and Inheritance)|url=https://docs.oracle.com/javase/tutorial/java/IandI/polymorphism.html|access-date=2020-07-11|website=docs.oracle.com}}</ref><ref>{{Cite web|title=9. Classes — Python 3.15.5 documentation|url=https://docs.python.org/3/tutorial/classes.html|access-date=2025-07-05|website=docs.python.org}}</ref> and do not provide a modifier to change this behavior. However, some languages provide modifiers to prevent methods from being overridden by derived classes (such as the ''final'' and ''private'' keywords in [[Java (programming language)|Java]]<ref>{{Cite web|title=Writing Final Classes and Methods (The Java™ Tutorials > Learning the Java Language > Interfaces and Inheritance)|url=https://docs.oracle.com/javase/tutorial/java/IandI/final.html|access-date=2020-07-11|website=docs.oracle.com}}</ref> and [[PHP]]<ref>{{Cite web|title=PHP: Final Keyword - Manual|url=https://www.php.net/manual/en/language.oop5.final.php|access-date=2020-07-11|website=www.php.net}}</ref>).
