Assessments and predictions of patient quality of life (QoL) permeate many veterinary decisions, including (1) whether to perform a procedure due to concurrent QoL issues, (2) whether a procedure will negatively affect QoL in the near or distant future, and (3) whether QoL is poor enough to warrant euthanasia. In order to understand how veterinarians manage decisions relating to patient well-being, interviews with 41 veterinarians and over 100 hours of observations of 10 veterinarians were conducted. Participants held diverse views regarding the type of parameters that should be included when defining QoL. Interestingly, they also held differing views about who should be assessing patient QoL, with some participants believing that animals' owners were better able to assess patient QoL than veterinarians. For these veterinarians, respecting the client's autonomy in deciding what was best for the patient weighed heavily in their decisions. Other veterinarians felt that they, rather than the client, were the best assessors of QoL and felt justified in persuading clients to follow a certain course of action (often considered a paternalistic approach). These findings raise some interesting questions for the profession. What role should veterinarians play when assessing patient QoL? When is paternalism acceptable or even mandatory in veterinary medicine? Does respecting client autonomy also require an evaluation of the client's abilities to make appropriate decisions for the patient? The lack of uniformity in defining and assessing patient QoL highlights the need for increased dialogue with respect to veterinarians' responsibilities to both animals and clients.