The present chapter is structured as follows. Section A introduces the concept of expenditure and its importance in the overall measurement and understanding of the tourism sector. Section B reviews the basic concepts and categories of tourism expenditure and their relationship with different forms of expenditure, and describes the different means of, and sources for, measuring inbound, domestic and outbound tourism expenditure. It also examines the means of presenting the resulting statistics and provides sample tables of results. The last section deals with measurement issues related to specific transactions that may arise.