All you basketball know-it-alls got it wrong ... Michael Jordan is NOT the G.O.A.T of college hoops -- so says Bill Walton, who tells TMZ Sports that honor belongs to Kareem!
We got the basketball legend just days after MJ was crowned king of ESPN's "College Basketball's Greatest of All Time Bracket" ... and he says the voters got it flat-out wrong.
Don't get it twisted -- Bill LOVES Jordan, saying he's "one of the greatest players, phenomenal" ... but he tells us he believes Kareem Abdul-Jabbar was just better.
"He has the records," Walton says of the former UCLA center. "He has the three championships."
Kareem -- a 1-seed to begin the event -- was shockingly upset in the bracket early on by nine-seeded Shaquille O'Neal.
MJ, meanwhile, ran the table as a 2-seed ... eventually beating Larry Bird in the bracket's championship.
As for how Kareem's college career at UCLA stacks up with Jordan's at UNC ... it seems Walton's got a point when you pull up those numbers.
Kareem -- who went by Lew Alcindor back then -- won three titles and averaged 26.4 points and 15.5 rebounds per game in his three-year career.
Jordan, meanwhile, won one championship while averaging 17.7 points and 5.0 rebounds per game in his three-year career.
Walton tells us he ain't too worried about the results, though ... and rightfully so, 'cause the guy's got an awesome virtual charity bike ride coming up this month -- where all the money raised is going toward COVID-19 relief efforts!!