Michael James LaCoss (born May 30, 1956) is an American former starting pitcher in Major League Baseball.

LaCoss made his major league debut in 1978, appearing in 18 games and recording an ERA of 4.50 LaCoss had a breakout season in 1979 for the division champion Reds, winning eight consecutive decisions at the start on his way to a 9-3 record and a berth on the National League All-Star team.

The American League squad had taken a 6-5 lead in the game and were threatening for more when LaCoss retired Don Baylor on a force play.

LaCoss then pitched a scoreless seventh as the NL came back to win with single runs in the eighth and ninth.

The first was off Dane Iorg, a utility player who entered the game to pitch for the San Diego Padres near the end of an 18–1 Giants blowout.