Artificial intelligence in cyber security refers to the use of machine learning, behavioural analytics, and automation technologies to detect, prevent, and respond to cyber threats in real time. In Australia, artificial intelligence in cyber security is increasingly critical as organisations align with the Australian Cyber Security Centre (ACSC) Essential Eight, APRA CPS 234, and ISO 27001 requirements. AI-powered systems analyse vast volumes of network traffic, user behaviour, and threat intelligence feeds to identify anomalies that traditional tools may miss. Artificial intelligence in cyber security enhances threat detection accuracy, reduces false positives, and accelerates incident response. It also supports predictive risk modelling and automated remediation workflows. For Australian enterprises and government agencies facing sophisticated cybercrime, AI-driven security capabilities strengthen resilience and improve governance visibility at executive and board levels.