The Washington Nationals' 2008 season was the fourth season for the franchise in the District of Columbia, and the 40th since the original team was started in Montreal, Quebec, in 1969. It also marked the first season the Nationals played at Nationals Park. The team finished in last place in the National League East with a record of 59–102, the worst record in Major League Baseball.

Nationals Park is a baseball stadium along the Anacostia River in the Navy Yard neighborhood of Washington, D.C. It is the ballpark of Major League Baseball's Washington Nationals. Since its completion in 2008, it was the first LEED-certified green major professional sports stadium in the United States.