Behaviours that challenge is a term used to describe a cluster of symptoms associated with the experiences of dementia. The biomedical perspective often refers to these as behavioural and psychological symptoms of dementia (BPSD). As the dementia progresses, many people living with dementia may experience and display certain behaviours that may be perceived by staff as a challenge. The key focus should be on the significance and meaning of the behaviour, as there is no behaviour displayed by a person living with dementia that does not have a meaning, but it is our inability to understand the significance of this that is the issue. Therefore, the key focus should be on establishing the underlying causes by undertaking a differential diagnosis to rule out other factors that may be contributing to the behaviour. This chapter will examine what behaviours that challenge is, the main causes, contributory factors and the person-centred approaches that need to be considered in the first instance to support the person.