Purpose <p>Older adult homicide is a preventable public health problem. It is an understudied area in general and not well understood in terms of interpersonal and other situational factors. This study aimed to describe older adult homicide in Australia for the period 2001–2018.</p> Method <p>The study was a retrospective population-based cross-sectional design, describing consecutive cases of older adult homicide victims (aged 65 years and older) reported to Australian coroners during the period 2001–2018. Data from the medico-legal investigation were extracted from the National Coronial Information System, presented using a modified social-ecological model (SEM). Chi-square and binary logistic regression analyses were performed to compare factors between family and non-family, as well as older adult and younger, adult homicide victimisation.</p> Results <p>There were 337 unique incidents and an average rate of 0.63 homicides per 100,000 population each year. Victims were frequently: male (56.1%), aged between 65 and 74 years (59.1%), killed at the home location (85.2%), and involved a blunt force (41.2%) mechanism. Perpetrators were most frequently intimate or familial relations (51.9%), followed by acquaintances (20.5%), or strangers (17.5%). By comparison, family homicide victims were most frequently female (62.3%). Older adult homicides, particularly those perpetrated by family members, were over-represented in multiple fatality events.</p> Conclusions <p>This study confirmed and clarified the unique characteristics of the older adult homicide, including two distinct family homicide typologies and drawing attention to multiple fatality events. Practitioners and researchers working in violence prevention and with older adults may use these findings to guide future research and prevention.</p>