Kotaro Oshio (押尾コータロー Oshio Kōtarō?) is an acoustic guitarist from Japan. Born in Osaka, on February 1, 1968, he is best known for his work on the steel string guitar. Oshio is a part of Sony Music Japan's SME Records division.

Oshio's music is classified within various categories including pop, new age, and jazz. Oshio's musical technique includes fingerpicking, tap harmonics, and a unique strumming style referred to as a "nail attack" in which he slaps the strings with the nails of his middle and ring fingers which is inspired by Michael Hedges. While his albums include mostly original material, Oshio is also known for his covers and movie soundtracks. His unique skill in interpretation and arrangement can be heard in tracks such as Merry Christmas, Mr. Lawrence from his album Starting Point.