This article is about the decade starting at the beginning of 2000 and ending at the end of 2009. For the century or millennium starting in 2000 (or, technically, 2001), see 21st century and 3rd millennium.

The 2000s decade refers to the years from 2000 to 2009, inclusive. Technically, however, the millennium began in 2001 because there is no such thing as the "year zero", but in informal and non technical settings the millennium usually began in 2000. Many individuals do have their own beliefs of when the 2000s decade began. Informally, it can also include a few years at the end of the preceding decade or the beginning of the following decade. Others believe it pop culturally began right on target in 2000 or around 2002. The decade could also begin pop culturally sometimes in the late 1990s, most likely around the year 1998 or 1999. Some also state that the symbolic beginning of the decade (and the 21st Century) was the 9/11 attacks, although others find this view pessimistic. Throughout the decade, the conservative George W. Bush presided over the many radical changes in technology and foreign policy in the United States.