Byron Scott -- NBA Champ Files for Divorce ... After 29 Year Marriage

3-time NBA champ Byron Scott has filed for divorce ... seeking to end his 29-year marriage to his college sweetheart Anita Scott ... TMZ Sports has learned.

According to court docs, obtained by TMZ Sports, the former Lakers player (who later served as head coach of the Cleveland Cavaliers) ... filed the papers on March 13.

Byron and Anita met at a nightclub in Los Angeles when Byron was still a student at Arizona State ... and according to Anita, he courted her with flowers, love letters and poetry.

Anita once told Cleveland.com, "Once we started dating, [Byron] was the knight in shining armor. He was the perfect sweetheart. It was a whirlwind."

They married in 1985 -- but according to the docs, they separated in June 2013.