The large number of unwanted cats in many modern communities results in a complex, worldwide problem causing many societal issues. These include ethical concerns about the euthanasia of many healthy animals, moral stress for the people involved, financial costs to organisations that manage unwanted cats, environmental costs, wildlife predation, potential for disease spread, community nuisance, and welfare concerns for cats.Humans contribute to the creation and maintenance of unwanted cat populations and also to solutions to alleviate the problem. The work in this thesis explored human factors contributing to the unwanted cat problem-including cat ownership perception, cat caretaking, cat semi-ownership and cat surrender-and human factors associated with cat adoption choices and outcomes.To investigate human factors contributing to the unwanted cat problem, data were collected from 141 people surrendering cats to four animal shelters. The aim was to better understand the people and human-cat relationships involved, and ultimately to inform strategies to reduce shelter intake.Participants were recruited for this study when they surrendered a cat to a shelter and information was obtained on their demographics, cat interaction history, cat caretaking, and surrender reasons.This information was used to describe and compare the people, cats, and human-cat relationships contributing to shelter intake, using logistic regression models and biplot visualisation techniques.A model of cat ownership perception in people that surrender cats to shelters was proposed. A revised questionnaire was then used to explore cat ownership perception in a broader population of 1013 Australians. Data were collected on demographic, attachment, and caretaking factors through an internet survey. A framework based on the Theory of Planned Behaviour was used to determine attitudes, beliefs, social norms, and perceived behavioural control factors associated with cat ownership perception.In the population of cat surrenderers, both cat owners and non-owners shared a common concern for cats and their welfare. The majority of non-owners interacted with, formed attachments to, and felt responsible for the cats they surrendered, but differed from owners in their level of caretaking. The extent of cat semi-ownership in the study population was considerable, emphasising the need for identification of semi-owners contributing to shelter intake. This could help direct strategies aimed at reducing unwanted cat numbers. Determinants of ownership perception in people surrendering cats included cat acquisition method, association time, closeness of the human-cat relationship, and III degree of responsibility for the cat's care. Detailed analysis of surrender reasons, which were usually multifactorial, highlighted the complexity of the unwanted cat problem. The results suggested that the collection of more detailed information by shelters at the time of surrender is warranted to guide strategies to prevent future surrenders.The internet survey from a ...