Masahiro Doi (土井 正博, Doi Masahiro) (born December 8, 1943) is a Japanese former professional baseball outfielder in Nippon Professional Baseball. He played for the Kintetsu Buffaloes from 1962 to 1974 and the Taiheiyo Club / Crown Lighter / Seibu Lions from 1975 to 1981. Despite a stellar 20-year career as a slugger (including 15 All-Star team selections), Doi never made it to the postseason or got a chance to play in the Japan Series. He last served as the batting coach for the Chunichi Dragons.