The OPC UA Object Model provides a consistent, integrated set of NodeClasses for representing Objects in the AddressSpace. This model represents Objects in terms of their Variables, Events and Methods, and their relationships with other Objects. OPC 10000-3 describes this model.

The OPC UA object model allows Servers to provide type definitions for Objects and their components. Type definitions may be subclassed. They also may be common or they may be system-specific. ObjectTypes may be defined by standards organizations, vendors, or end-users.

This model allows data, Alarms and Events, and their history to be integrated into a single Server. For example, Servers are able to represent a temperature transmitter as an Object that is composed of a temperature value, a set of alarm parameters, and a corresponding set of alarm limits.