Yahoo! Inc. NASDAQ: YHOO is an American computer services company with a mission to "be the most essential global Internet service for consumers and businesses". It operates an Internet portal, the Yahoo! Directory and a host of other services including the popular Yahoo! Mail. It was founded by Stanford graduate students David Filo and Jerry Yang in January 1994 and incorporated on March 2, 1995. The company is headquartered in Sunnyvale, California.

According to Alexa Internet and Netcraft, both of which are Web trends companies, Yahoo! is the most visited website on the Internet today. The global network of Yahoo! websites received 3.4 billion page views per day on average as of October 2005.