Modern pig housing environments provide animals with essential resources, but from an animal’s point of view, they are quite barren and deprive them of the opportunity to make full use of their natural behavioural repertoire and actively work for these resources. The lack of stimulation resulting from such environments compromises animal welfare. This issue can be addressed by providing environmental enrichment, which comprises all aspects of an animal’s environment that facilitate engagement in species-specific behaviours. In this chapter, we provide an overview of different types of enrichment, ranging from artificial point-source objects to social and cognitive enrichment. We discuss the existing body of evidence for welfare-enhancing effects of different enrichment, focussing on whether potential enrichment promotes natural behaviours, reduces abnormal behaviours, and whether effects are sustainable over the long-term. We conclude with a comparative evaluation of enrichment from an animal welfare perspective, highlighting the potential of social and cognitive enrichment.