2000 (MM) was a leap year that started on a Saturday, in accordance with the Gregorian Calendar. It was the 2000th year in the Anno Domini/Common Era, and the last year of the 20th century and of the 2nd millennium. It was also the first century leap year since 1600.

2000 was designated as:

• International Year for the Culture of Peace
• World Mathematical Year

2000 was also the first year of the 2000s decade. Popular culture holds the year 2000 as the first year of the 21st century and the 3rd millennium, due to a tendency to group the years according to decimal values, as if year zero were counted. According to the Gregorian Calendar this distinction falls to the year 2001, because the first century was retroactively said to start with year AD 1. Since the calendar has no year zero, its first millennium spans from years 1 to 1000, inclusive, and its second millennium from years 1001 to 2000. (See more at Millennium.)

The year 2000 was the subject of Y2K concerns: fears that computers would not shift from 1999 to 2000 correctly. However, by the end of 1999, many companies had already converted to new, or upgraded their existing, software. Some even obtained Y2K certification. In the actual event, relatively few problems occurred.