Simple SummaryIn the face of a global biodiversity decline, zoos worldwide play important roles in conservation via efforts such as providing breeding programmes and reintroductions into the wild. Zoo populations are important as a buffer against extinction, but substantial differences between the wild and zoo environments can lead to health issues. These problems, in turn, can impact the reproductive success of individuals. Consequently, some primate species have reduced breeding success when housed in zoos compared to their wild counterparts. To prevent the onset of behavioural, physiological, and cognitive negative effects and to continually improve the welfare of their animals, zoos widely implement different types of environmental enrichment. Enrichment can take many forms, but sensory enrichments are less studied. Scent enrichments are less utilized despite multiple research studies showing that they may affect positively the well-being of zoo-housed animals, including non-human primates. Despite being traditionally considered to have a poor sense of smell, more evidence is emerging to suggest that olfaction is important in primates. This review article therefore focuses on scent-based enrichment and the specifics of primate olfaction.AbstractZoos worldwide play an important role in both in situ and ex situ conservation via efforts such as providing breeding programmes and reintroductions into the wild. Zoo populations are crucial as a buffer against extinction. However, a mismatch between the wild and zoo environments can lead to psychological as well as physiological health issues, such as stress, boredom, diabetes, and obesity. These problems, in turn, can impact the reproductive success of individuals. Consequently, some primate species have reduced breeding success when housed in zoos compared to their wild counterparts. To prevent the onset of behavioural, physiological, and cognitive negative effects and to continually improve the welfare of their animals, zoos widely implement different types of environmental enrichment. There are many forms enrichment can take, such as feeding, puzzles and training, but sensory enrichments, including implementing the use of scents, are currently understudied. Scent enrichments are less utilized despite multiple research studies showing that they may have positive effects on welfare for zoo-housed animal species, including non-human primates. Despite being traditionally considered to be microsmatic, various lines of evidence suggest that olfaction plays a larger role in primates than previously thought. This review therefore focuses on scent-based enrichment and the specifics of captive primates.