This thesis is an investigation of the prevalence of meat-avoidance amongst pet keepers, the prevalence of plant-based feeding practices, and the motivations and concerns of pet keepers regarding animal- and plant-based pet foods. A questionnaire was disseminated online to English-speaking pet keepers (n = 3,673), and descriptive statistics were utilised. Few pets were fed strictly plant-based diets (1.6%; 59/3,673). One dog was kept by a vegetarian, otherwise vegans were the only pet keepers who fed plant-based diets to their pets, with 27% (58/212) doing so. Consideration of animal rights and lack of concern regarding plant-based diets being unnatural were most significantly associated with vegan pet keepers feeding plant-based diets to their pets (OR 9.12 and 14.27 respectively, p < 0.05). A large proportion (45%; 269/599) of pet keepers reported desire for evidence regarding nutritional adequacy of plant-based diets for pets; more research in this area is clearly warranted.