The ACSC Essential 8 maturity model is a structured framework used to measure how effectively an organisation has implemented the Essential Eight cybersecurity mitigation strategies. Developed by the Australian Cyber Security Centre, the model defines four maturity levels—Level 0 through Level 3—that represent increasing degrees of protection against cyber threats. Each level describes how consistently and comprehensively the Essential Eight controls are applied across systems and environments. In Australia, many government agencies and organisations working with government data are expected to assess and report their Essential Eight maturity levels as part of cybersecurity governance programs. The maturity model helps organisations identify gaps, prioritise remediation efforts, and track security improvements over time. By progressing through the maturity levels, businesses can strengthen their resilience against sophisticated cyberattacks and demonstrate alignment with national cybersecurity expectations and best practice risk management.