The assessment of animal welfare relates to investigations of how animals try to cope with their environment, and how easy or how difficult it is for them to do so. The use of rigorous scientific methods to assess this has grown over the past few decades, and so our understanding of the needs of animals has improved during this time. Much of the work in the field of animal welfare has been conducted on farm animals, but it is important to consider how the methods and approaches used in assessing farm animal welfare have been, and can be, adapted and applied to the measurement of welfare in animals in other domains, such as in zoos. This is beneficial to our understanding of both the theoretical knowledge, and the practicability of methods. In this article, some of the commonly-used methods for measuring animal welfare will be discussed, as well as some practical considerations in assessing the welfare of zoo animals.