It was the second straight year the award has gone to a member of the Seattle Mariners.
Major League Baseball has presented the award each year since 1971 to the player who best exemplifies the game of baseball, sportsmanship, community involvement and the individual's contribution to his team.
"I grew up idolizing Roberto Clemente," said Martinez, 41. "Watching him play in the 1971 World Series is one of the main factors in me playing baseball. I have always admired him, as a player and a person."
Martinez, a native of Puerto Rico like Clemente, is a seven-time All-Star with 309 career home runs and 1,261 runs batted in. He retired following the 2004 season.