A provider definition represents software that implements the semantics of one or more operations on an object in an object-oriented system. A provider represents a specific instance of a provider definition. One or more providers implement operations for objects in the system. A component of the system called the provider registry maintains a mapping of providers and operations as defined by the provider definitions. When handling a request to invoke a operation on an object, the system dynamically dispatches to the correct provider based on this mapping. Where more than one provider are registered as implementing the desired operation on an object, techniques are disclosed for selecting a provider to perform the desired operation.