Animal welfare relates to the feelings, behavior, and the health status of animals. Nevertheless, animal welfare legislation rarely prescribes what animals should feel or experience, but rather what humans should do to protect the animals in their care from unnecessary suffering, and e.g., specifications to provide them with suitable housing conditions and appropriate feed to ensure a reasonably good life. This obviously applies to domesticated animals and wildlife kept in enclosures, but not to free-roaming wildlife. Wildlife welfare has received far less attention than welfare for farm or companion animals, although attempts have been made. In recent years the extent of interest in wildlife welfare has grown, as more people have realized that humans have a substantial influence on the lives and welfare of wildlife individuals. Humans, as individuals and as a species, intentionally or unintentionally influence the welfare of wildlife in many different ways, some of which are discussed in this special issue.