The teams meet Friday in Seattle, giving the Zags (32-2) the chance to play in their home state.
Gonzaga was in contention for a No. 1 seed for much of the season thanks to its strong offense led by Kyle Wiltjer (16.7 points), then won the West Coast Conference Tournament for the third straight season. Gonzaga shot a national-best 52.4 percent and is in its 17th straight NCAA Tournament appearance.
North Dakota State (23-9) won the Summit League title for its second straight NCAA trip. The Bison are led by senior guard Lawrence Alexander, who averaged 18.9 points and shot 44 percent from 3-point range.