The term derived class relates to the inheritance of data and functions from a base class (which can also be referred to as a superclass). The derived class is a specialization of the base class. It contains all the features of the base class plus additional features unique to it.

Derived classes assume a prominent role in object-oriented programming design. In object-oriented programming each object has defined properties, which allows the object to assume a set function. The properties, and the corresponding function of an object, should be unique from those of other objects. However, objects can form groups with a common theme. This relatedness of objects can be beneficial in terms of programming function and programmers' time. Faced with this similarity, but needing to preserve the uniqueness of objects, the formation of derived classes preserves both grouping similarity and functional uniqueness.

The increased specialization of a derived class, relative to the parental base class, can be created in two ways. One way is by the addition of new data or functions of the data. The other way is by modifying the functions that are already in place.

Another invocation of the term subclass is in the Java programming language. Specifically, related applets--mini-programs that operate within another program--can be generated by creating applet subclasses from an applet class.