The present document specifies the stage 3 protocol and data model for the Policy Control Event Exposure Service of the 5G System. It provides stage 3 protocol definitions@ message flows and specifies the API for the Npcf Event Exposure service. The 5G System stage 2 architecture and the procedures are specified in 3GPP TS 23.501 [2]@ 3GPP TS 23.502 [3] and 3GPP TS 23.503 [4]. The 5G System stage 3 call flows are provided in 3GPP TS 29.513 [8]. The Technical Realization of the Service Based Architecture and the Principles and Guidelines for Services Definition are specified in 3GPP TS 29.500 [5] and 3GPP TS 29.501 [6]. The Policy Control Event Exposure Service is provided by the Policy Control Function (PCF). This service exposes policy control events observed at the PCF.