LOOPS, the object system for Interlisp-D, was influenced by Smalltalk and Flavors, and a paper about it was published in 1982. In 1981, Goldberg edited the August issue of Byte Magazine, introducing Smalltalk and object-oriented programming to a wide audience. The Flavors object-oriented Lisp was developed starting 1979, introducing multiple inheritance and mixins. ĭuring the late 1970s and 1980s, object-oriented programming rose to prominence. While Smalltalk was influenced by the ideas introduced in Simula 67 it was designed to be a fully dynamic system in which classes could be created and modified dynamically. Smalltalk went through various versions and interest in the language grew. Smalltalk became noted for its application of object orientation at the language-level and its graphical development environment. Smalltalk-72 included a programming environment and was dynamically typed, and at first was interpreted, not compiled. In the 1970s, the first version of the Smalltalk programming language was developed at Xerox PARC by Alan Kay, Dan Ingalls and Adele Goldberg. A 1976 MIT memo co-authored by Barbara Liskov lists Simula 67, CLU, and Alphard as object-oriented languages, but does not mention Smalltalk. Although sometimes called 'the father of object-oriented programming', Alan Kay has differentiated his notion of OO from the more conventional abstract data type notion of object, and has implied that the computer science establishment did not adopt his notion. Kay used the term 'object-oriented programming' in conversation as early as 1967. Influenced by the work at MIT and the Simula language, in November 1966 Alan Kay began working on ideas that would eventually be incorporated into the Smalltalk programming language. I thought of objects being like biological cells and/or individual computers on a network, only able to communicate with messages (so messaging came at the very beginning – it took a while to see how to do messaging in a programming language efficiently enough to be useful). The object-oriented Simula programming language was used mainly by researchers involved with physical modelling, such as models to study and improve the movement of ships and their content through cargo ports.

Simula introduced important concepts that are today an essential part of object-oriented programming, such as class and object, inheritance, and dynamic binding. Independently of later MIT work such as AED, Simula was developed during the years 1961–1967. Topics such as data abstraction and modular programming were common points of discussion at this time. Also, in 1968, an MIT ALGOL version, AED-0, established a direct link between data structures ('plexes', in that dialect) and procedures, prefiguring what were later termed 'messages', 'methods', and 'member functions'. Another early MIT example was Sketchpad created by Ivan Sutherland in 1960–1961 in the glossary of the 1963 technical report based on his dissertation about Sketchpad, Sutherland defined notions of 'object' and 'instance' (with the class concept covered by 'master' or 'definition'), albeit specialized to graphical interaction. 'Object' referred to LISP atoms with identified properties (attributes). Terminology invoking 'objects' in the modern sense of object-oriented programming made its first appearance at the artificial intelligence group at MIT in the late 1950s and early 1960s. Significant object-oriented languages include Ada, ActionScript, C++, Common Lisp, C#, Dart, Eiffel, Fortran 2003, Haxe, Java,, Kotlin, Logo, MATLAB, Objective-C, Object Pascal, Perl, PHP, Python, R, Raku, Ruby, Scala, SIMSCRIPT, Simula, Smalltalk, Swift, Vala and Visual Basic.NET. Many of the most widely used programming languages (such as C++, Java, Python, etc.) are multi-paradigm and they support object-oriented programming to a greater or lesser degree, typically in combination with imperative programming, procedural programming and functional programming. In OOP, computer programs are designed by making them out of objects that interact with one another. Object-oriented programming ( OOP) is a programming paradigm based on the concept of objects, which can contain data and code: data in the form of fields (often known as attributes or properties), and code in the form of procedures (often known as methods). Through inheritance, a subclass can be created as a subset of the Button class. This Button class has variables for data, and functions.

For other meanings of object-oriented, see Object-orientation.

Package diagram visual paradigm