The 2008 Slammiversary was a professional wrestling pay-per-view (PPV) event produced by the Total Nonstop Action Wrestling (TNA) promotion that took place on June 8, 2008 at the DeSoto Civic Center in Southaven, Mississippi. It was the fourth event under the Slammiversary name and the sixth event in the 2008 TNA PPV schedule. Seven professional wrestling matches and one dark match were featured on the event's card, three of which were for championships. The event commemorated TNA's six year anniversary.

The main event was a King of the Mountain match for the TNA World Heavyweight Championship, in which then-champion Samoa Joe defended against Booker T, Christian Cage, Rhino, and Robert Roode. Joe won the match to retain the title. The card also featured a bout pitting A.J. Styles against Kurt Angle, which Styles won. The TNA World Tag Team Championship was defended by The Latin American Xchange (Hernandez and Homicide; LAX) against Team 3D (Brother Devon and Brother Ray) at the event. LAX was the victors in the contest to retain the championship. A Six Woman Tag Team match was won by the team of Gail Kim, ODB, and Roxxi over The Beautiful People (Angelina Love and Velvet Sky) and Moose on the undercard.

Slammiversary is remembered for Joe being the first to retain a championship in a King of the Mountain match. 20,000 was the reported figure of purchasers for the event by The Wrestling Observer Newsletter. Slammiversary had an attendance of 2,000 people. Jon Waldman of the professional wrestling section of the Canadian Online Explorer rated the show a 7 out of 10, which was lower than the 8 out of 10 given to the 2007 edition by Jason Clevett. After the event, an accident occurred which resulted in the death of one man and the injury of another.