During his high school tenure he led Oklahoma Christian School (where his father was also his head coach) to four state championships.
For the 2004–2005 season (his sophomore year), he was named to the "Little All-City All-State" team while averaging 13.6 points per game (PPG), and his brother, Taylor, was named "Player of the Year" by The Oklahoman.
As a junior (2005–2006 season), he was named "Player of the Year" by The Oklahoman. In 26 games Griffin averaged 21.7 PPG, 12.5 RPG, and 4.9 assists per game (APG), and blocked 49 shots with 45 steals. He was also named to the Tulsa World "Boys All-State First Team".
During 2006–2007 (his senior season) he averaged 26.8 PPG, 15.1 RPG, and 4.9 APG. Griffin was named the Oklahoma "Player of the Year" by both the Tulsa World and The Oklahoman. Additionally, he was Gatorade's "Oklahoma Player of the Year" and named to the 2007 McDonald's All-American and Jordan All-American teams. At the McDonald's All-American game in Louisville, Kentucky he won the slam dunk contest.
College career
As a freshman (the 2007–2008 season) at Oklahoma, Griffin averaged 14.7 PPG and 9.1 RPG, and led the Sooners to a 23-12 record
Griffin was named to the Big 12 Conference "First Team" and also the "All Rookie First Team" (the last Sooner to make the conference "All-Rookie" team was Wayman Tisdale in 1983 for the Big Eight Conference).
2008-2009 Season
Griffin finished the season with a Big 12 Conference record of 30 double-doubles, which was one short of the NCAA record set by David Robinson with 31, set in 1986-1987. He also set a record for the most rebounds in Big 12 Conference history in a single-season, with 504, and won the 2008-2009 MVP.