The 1938–39 Long Island Blackbirds men's basketball team represented Long Island University during the 1938–39 NCAA men's basketball season in the United States. The head coach was Clair Bee, coaching in his eighth season with the Blackbirds. The team finished the season with a 23–0 record and was retroactively named the national champion by the Helms Athletic Foundation and the Premo-Porretta Power Poll. They won the second-ever National Invitation Tournament (NIT) as well, going 3–0 in the tournament with a win over Loyola of Chicago in the championship game.
Schedule and results
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!colspan=9 style="background:#000000; color:#FFFFFF;"| Regular season
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!colspan=9 style="background:#000000; color:#FFFFFF;"| National Invitation Tournament