Business intelligence encompasses all activities dealing with collecting, storing/-managing, and analyzing business-relevant data with the objective of generating knowledge as input to decision support. Business intelligence is often used as an umbrella term for data warehousing, reporting and OLAP (online analyticalprocessing), MIS/DSS, and data mining, respectively. If we count all topics listed above, it is obvious that business intelligence hasquite a long history also in the tourism domain. As early examples in tourism,we can identify the DINAMO system introduced by American Airlines alreadyin 1988 or TourMIS in 1998.The widespread use of ICT, especially the uptake of the Internet and social media, led to an increase of available data on customers, competitors, and thewhole market in all major business domains, including tourism. More powerful hardware and sophisticated methods to store and analyze such data turned business intelligence into one of the fastest-growing technologies and most challenging areas in the last decade. This chapter gives an overview on the topic of business intelligence and all technical components of a BI architecture (i.e., information extraction and transformation, data warehousing, and different mechanisms and tools to access and analyze data, like reporting or OLAP tools, dashboards, or data mining tool sets). Moreover, the chapter looks at the history of BI in tourism and presents and discusses typical application scenarios in tourism. Finally, we look at currenttrends and latest developments in the area of business intelligence and their expected implications for the tourism domain.