According to the Star Tribune, Dieng is the fifth Wolves rookie to win the award. Ricky Rubio, Kevin Love, Randy Foye and Stephon Marbury are the others.
Dieng averaged 8.6 points and 8.3 rebounds during March, but he averaged 12.1 points and 12 rebounds a game in the last nine games, including six starts when he replaced the injured Nikola Pekovic.
He became the first player since Elden Campbell in 1991 to score 10 points, 10 rebounds and five blocked shots in his first NBA start, according to the Star Tribune.
Dieng became the fifth Timberwolves player in team history to score 20 points and grab 20 rebounds in the same game, against Houston on March 20.
Dieng will likely become the team's starter again. Pekovic left Monday's game against the Clippers when his bothersome ankle flared up again.