Simple SummaryCats are popular pets in Australia, being present in around one-third of households. As pets, cats are managed in a wide variety of ways, from fully indoors in apartments to completely outdoor free roaming. Australian wildlife is uniquely vulnerable to cat predation. Roaming cats also create a nuisance and are at risk of accidents and injuries. Councils, veterinarians, animal welfare organisations and conservation groups all have an interest in encouraging cat owners to change their behaviour and prevent their cats from roaming. Understanding what influences cat owner decisions can help design effective programs. This study asked cat owners about their cats, living circumstances, current cat management behaviour and agreement with statements reflecting their ability to contain their cats and their social opportunity and motivation to do so. More than half of participating cat owners already fully contain their cats. The most important influence for cat owners to keep their cats contained was having the skills, knowledge and belief that they could do so successfully. Those who lived in apartments, were renting or were motivated by their cat’s safety, to protect wildlife or to care for their community were also more likely to contain their cats.AbstractThere are over 5 million pet cats in Australia managed on a spectrum from fully indoors to completely outdoor free roaming. Roaming cats threaten biodiversity, can create a nuisance and are at risk of accidents and injury. Hence, there is substantial interest in behaviour change interventions to increase cat containment. An online questionnaire collected information on cat owner demographics, the number of cats owned, current containment behaviours and an agreement with 15 capability, opportunity and motivation (COM) items. Responses were received from 4482 cat owners. More than half (65%) indicated that they currently keep their cat(s) fully contained. Another 24% practiced a night curfew. Owners’ psychological capability had the greatest influence on containment behaviour. Motivation (community- and cat welfare-framed), living in an apartment and renting were also associated with a greater likelihood of containment. Cat owners not currently containing their cats could be divided into six profiles who differed on agreement with COM themes, age, future intentions, current behaviour, location and gender. Understanding differences between cat owner segments can assist with designing behaviour change interventions. Increasing cat owners’ psychological capability to contain their cats and encouraging the adoption of a night curfew as a first step towards 24 h containment are recommended.