Bautista picked up the award from the Toronto chapter of the Baseball Writers' Association of America following a return to form. He recorded a team-high 22 RBIs during the past month while matching Edwin Encarnacion for the lead in homers, with nine.
The 31-year-old hit .257 while also scoring 20 runs, with four doubles and 13 walks. Bautista entered play on Friday night against Boston hitting .233 with 12 homers, 32 RBIs and a .779 OPS in 51 games this season.
Brandon Morrow (4-2, 3.50 ERA, two shutouts), Casey Janssen (0-0, 1.59 ERA, five saves), J.P. Arencibia (.278, eight homers, 19 RBIs), Encarnacion (.234, nine homers, 21 RBIs) and Kelly Johnson (.272, five homers, 18 RBIs) also received votes for their work during May.
Honda will make a donation to the charity of Bautista's choosing as part of the award.