The 2003 NCAA Division III Men's Ice Hockey Tournament was the culmination of the 2002–03 season, the 20th such tournament in NCAA history. It concluded with Norwich defeating Oswego State in the championship game 2-1. All First Round and Quarterfinal matchups were held at home team venues, while all succeeding games were played in Northfield, Vermont, where Norwich University coincidentally hosted the Frozen Four the year they won.

The following teams qualified for the tournament. Automatic bids were offered to the conference tournament champion of seven different conferences with one at-large bid for the best remaining team from each region.

The tournament featured four rounds of play. All rounds were Single-game elimination. For the three eastern Quarterfinals, the teams were seeded according to their rankings with the top three teams serving as hosts. For the western quarterfinal, the top-ranked team awaited the winner of a play-in game between the lower-ranked teams. The quarterfinal brackets were arranged so that were all higher-seeded teams to advance, the first overall seed would play the fourth overall seed in the semifinals.

Note: * denotes overtime period(s)