Hiroyuki Kobayashi (?? ??, ???, Kobayashi Hiroyuki, Kobayashi-Hiro, born June 4, 1978 in Soka, Saitama, Japan) is a Japanese right-handed pitcher.
He played in the 2006 World Baseball Classic for Japan.
As a relief pitcher Kobayashi throws a fastball that sits in 87-91 mph (tops out at 93 mph), silder, change-up, and an effective forkball as his out pitch.