Ogasawara Sadamune (小笠原貞宗, 1292–1347) was a Japanese nobleman and a major figure in the formation of the Ogasawara-ryū.

A close ally of Ashikaga Takauji, Ogasawara was placed in charge of court etiquette.

[1] His approach to etiquette was influenced by Seisetsu Shōhō (Ch'ing-cho Cheng-ch'eng), with whom Ogasawara studied Zen Buddhism and Chinese literature.

[2] Having inherited the headmastership of his family's school of kyujutsu and yabusame, he was archery instructor to both Takauji and Emperor Go-Daigo.

[5] Despite having instructed Emperor Go-Daigo, Ogasawara sided with the Northern Court during the Nanboku-chō period, and was given control the province of Shinano.