Responsibility-driven design is a design technique in object-oriented programming, which improves encapsulation by using the client–server model. It focuses on the contract by considering the actions that the object is responsible for and the information that the object shares. It was proposed by Rebecca Wirfs-Brock and Brian Wilkerson.

Responsibility-driven design is in direct contrast with data-driven design, which promotes defining the behavior of a class along with the data that it holds. Data-driven design is not the same as data-driven programming, which is concerned with using data to determine the control flow, not class design.

In the client–server model they refer to, both the client and the server are classes or instances of classes. At any particular time, either the client or the server represents an object. Both the parties commit to a contract and exchange information by adhering to it. The client can only make the requests specified in the contract and the server must answer these requests. Thus, responsibility-driven design tries to avoid dealing with details, such as the way in which requests are carried out, by instead only specifying the intent of a certain request. The benefit is increased encapsulation, since the specification of the exact way in which a request is carried out is private to the server.

To further the encapsulation of the server, Wirfs-Brock and Wilkerson call for language features that limit outside influence to the behavior of a class. They demand that the visibility of members and functions should be finely grained, such as in Eiffel programming language. Even finer control of the visibility of even classes is available in the Newspeak programming language.

Responsibility-driven design focuses on the objects as behavioral abstractions which are characterized by their responsibilities. The CRC-card modelling technique is used to generate these behavioral abstractions. The rest of the object structure including data attributes are assigned later, as and when required. This makes the design follow type hierarchy for inheritance which improves encapsulation and makes it easier to identify abstract classes. It can also group the classes together based on their clients which is considered a unique ability.

A good object-oriented design involves an early focus on behaviors to realize the capabilities meeting the stated requirements and a late binding of implementation details to the requirements. This approach especially helps to decentralize control and distribute system behavior which can help manage the complexities of high-functionality large or distributed systems. Similarly, it can help to design and maintain explanation facilities for cognitive models, intelligent agents, and other knowledge-based systems.

In their book Object Design: Roles, Responsibilities and Collaborations, the authors describe the following building blocks that make up responsibility-driven design.

Objects are described as things that have machine-like behaviors that can be plugged together to work in concert. These objects play well-defined roles and encapsulate scripted responses and information.