An apparatus and method for providing a context-aware service are provided. The apparatus includes a context-aware service object (CAS) management module managing information on a CAS and a context defined by the CAS, a sensor management module managing information on a sensor and requesting the sensor to observe knowledge, and a context management module informing the CAS management module of a CAS defining a context provided by the CAS management module when observed knowledge satisfies the context defined by the CAS, wherein upon being informed of the CAS by the context management module, the CAS management module requests the CAS to provide a service.