Karl won the award for the second straight month as the Nuggets continue their impressive turnaround.
In March, the Nuggets were an impressive 12-2 with both losses coming to the Western Conference-leading Phoenix Suns. Denver's loss to Phoenix on March 13 snapped an eight-game winning streak, its longest since the 1987-1988 season.
"This is truly a team award," Karl said. "The players have really put forth the effort and commitment that it takes to win and the coaching staff has worked tirelessly to prepare them for each game."