The course provides a short introduction to essential machine learning (ML) approaches, followed by a comprehensive overview of ML applications for cybersecurity defence. The defence mechanisms include spam mail classification, network intrusion detection, malware classification and analysis, threat intelligence, ML-based risk-based authentication, and ML applications in digital forensics. Additionally, the course explores the use of machine learning as a tool for attackers, encompassing topics such as circumventing cyber defences (e.g., breaking CAPTCHAs) and optimizing cyber attacks with machine learning.