<p><strong>Arson causes significant harm to individuals, environments, and communities across the world. Despite the impacts of this behaviour, few theory-driven empirical classification structures exist to guide the investigation and prevention of arson in the socio-cultural context of Aotearoa New Zealand. This thesis aimed to produce person- and crime-scene-centred typologies of adult firesetting uniquely adapted to this cultural context and to test the associations between emergent offender and offence subtypes and repeat firesetting. Researchers coded court files from 328 individuals convicted of arson in Aotearoa New Zealand for demographic, developmental, behavioural, psychological, fire-specific, and crime scene variables. Two typologies, one including offender characteristics and one including behavioural and crime scene characteristics, were developed using multidimensional scaling (MDS). The relationship between the different subtypes and repeat firesetting was also examined. Three subtypes of offender characteristics (Antisocial, Emotionally Expressive, and Mental Health Loneliness) and three subtypes of offence characteristics (Thrill-Seeking, Communicating Distress, and Family Harm) emerged from these analyses. While no offender subtypes were associated with repeat firesetting, the Thrill-Seeking offence subtype showed a significant association with repeat firesetting, and the Family Harm offence subtype demonstrated a significant association with one-time firesetting. The offender typology has practice implications for locating meaningful mental health treatment targets, and the offence typology has practice implications for directing the scope of arson investigations.</strong></p>