The 1987 Big Sky Conference Men's Basketball Tournament was held March 5–7 at the Walkup Skydome at Northern Arizona University in Flagstaff, Arizona. Seventh-seeded Montana State upset fourth-seeded rivals Montana in the championship game, 92–81, to clinch their second Big Sky men's basketball tournament. This year's tournament saw the top three states, Montana State, Montana, and Boise State, all lose in the first round. The Bengals received an automatic bid to the 1987 NCAA Tournament. No other Big Sky members were invited to the tournament.